feat(dns): allow setting an externally managed cluster domain (uc dns set)

* feat: add uc dns set

This allows manual setting of the cluster's domain name. I use this to
make the local cluster admin aware that this has been done.
(and then manually update the external dns)

```
% uc dns set ctrl.u.science.ru.nl
Set cluster domain: ctrl.u.science.ru.nl
Deploy the Caddy reverse proxy service ('uc caddy deploy') to enable internet access to your services via the reserved or your custom domain.

% uc dns show
ctrl.u.science.ru.nl

% uc dns set ctrl.u.science.ru.nl
Error: domain already reserved

% uc dns release
Released cluster domain: ctrl.u.science.ru.nl
```

See: #37

Signed-off-by: Miek Gieben <miek@miek.nl>

* docs

Signed-off-by: Miek Gieben <miek@miek.nl>

* check validatity

Signed-off-by: Miek Gieben <miek@miek.nl>

* No need to call out to update anything, as set doesnt use uncloud dns

Signed-off-by: Miek Gieben <miek@miek.nl>

* Ignore domain when there is no endpoint

Prevents this error, when you know what you're doing:

    Error: failed to update DNS records pointing to caddy service: create cluster domain records in Uncloud DNS: rpc error: code = Unknown desc = Post "/domains/ctrl.u.science.ru.nl/records": unsupported protocol scheme ""

Signed-off-by: Miek Gieben <miek@miek.nl>

* from main

Signed-off-by: Miek Gieben <miek@miek.nl>

* mise proto && make cli-docs

Signed-off-by: Miek Gieben <miek@miek.nl>

* Rebase and and generate protos again

Signed-off-by: Miek Gieben <miek@miek.nl>

* Rebase and fix

Signed-off-by: Miek Gieben <miek@miek.nl>

* feat(dns): allow setting an externally managed cluster domain

---------

Signed-off-by: Miek Gieben <miek@miek.nl>
Co-authored-by: Pasha Sviderski <me@psviderski.name>

website/docs/9-cli-reference/uc.md

@@ -18,7 +18,7 @@ A CLI tool for managing Uncloud resources such as machines, services, and volume
 * [uc caddy](uc_caddy.md)	 - Manage Caddy reverse proxy service.
 * [uc ctx](uc_ctx.md)	 - Switch between different cluster contexts. Contains subcommands to manage contexts.
 * [uc deploy](uc_deploy.md)	 - Deploy services from a Compose file.
-* [uc dns](uc_dns.md)	 - Manage cluster domain in Uncloud DNS.
+* [uc dns](uc_dns.md)	 - Manage the cluster domain.
 * [uc exec](uc_exec.md)	 - Execute a command in a running service container.
 * [uc image](uc_image.md)	 - Manage images on machines in the cluster.
 * [uc images](uc_images.md)	 - List images on machines in the cluster.

website/docs/9-cli-reference/uc_dns.md

@@ -1,12 +1,14 @@
 # uc dns
 
-Manage cluster domain in Uncloud DNS.
+Manage the cluster domain.
 
 ## Synopsis
 
-Manage cluster domain in Uncloud DNS.
+Manage the cluster domain.
 DNS commands allow you to reserve or release a unique 'xxxxxx.uncld.dev' domain for your cluster. When reserved, Caddy service deployments will automatically update DNS records to route traffic to the services in the cluster.
 
+EXPERIMENTAL: Use 'uc dns set' to configure an externally managed domain instead. Uncloud does not manage DNS records for manually set domains.
+
 ## Options
 
 ```
@@ -27,5 +29,6 @@ DNS commands allow you to reserve or release a unique 'xxxxxx.uncld.dev' domain
 * [uc](uc.md)	 - A CLI tool for managing Uncloud resources such as machines, services, and volumes.
 * [uc dns release](uc_dns_release.md)	 - Release the reserved cluster domain.
 * [uc dns reserve](uc_dns_reserve.md)	 - Reserve a cluster domain in Uncloud DNS.
+* [uc dns set](uc_dns_set.md)	 - Set or unset an externally managed cluster domain (EXPERIMENTAL).
 * [uc dns show](uc_dns_show.md)	 - Print the cluster domain name.
 

website/docs/9-cli-reference/uc_dns_release.md

@@ -23,5 +23,5 @@ uc dns release [flags]
 
 ## See also
 
-* [uc dns](uc_dns.md)	 - Manage cluster domain in Uncloud DNS.
+* [uc dns](uc_dns.md)	 - Manage the cluster domain.
 

website/docs/9-cli-reference/uc_dns_reserve.md

@@ -24,5 +24,5 @@ uc dns reserve [flags]
 
 ## See also
 
-* [uc dns](uc_dns.md)	 - Manage cluster domain in Uncloud DNS.
+* [uc dns](uc_dns.md)	 - Manage the cluster domain.
 

website/docs/9-cli-reference/uc_dns_set.md

@@ -0,0 +1,40 @@
+# uc dns set
+
+Set or unset an externally managed cluster domain (EXPERIMENTAL).
+
+## Synopsis
+
+EXPERIMENTAL: Set the cluster domain used to generate ingress hostnames for services.
+Configure wildcard DNS records for this domain with your DNS provider. Uncloud will not create, verify, update, or delete external DNS records.
+Pass an empty string to unset a manually set domain. Use 'uc dns release' to release a domain reserved in Uncloud DNS. Setting or unsetting the domain does not change existing service hostnames.
+
+```
+uc dns set DOMAIN_NAME [flags]
+```
+
+## Examples
+
+```
+  uc dns set apps.example.com
+  uc dns set ""
+```
+
+## Options
+
+```
+  -h, --help   help for set
+```
+
+## Options inherited from parent commands
+
+```
+      --connect string          Connect to a remote cluster machine without using the Uncloud configuration file. [$UNCLOUD_CONNECT]
+                                Format: [ssh://]user@host[:port], ssh+go://user@host[:port], tcp://host:port, or unix:///path/to/uncloud.sock
+  -c, --context string          Name of the cluster context to use (default is the current context). [$UNCLOUD_CONTEXT]
+      --uncloud-config string   Path to the Uncloud configuration file. [$UNCLOUD_CONFIG] (default "~/.config/uncloud/config.yaml")
+```
+
+## See also
+
+* [uc dns](uc_dns.md)	 - Manage the cluster domain.
+

website/docs/9-cli-reference/uc_dns_show.md

@@ -23,5 +23,5 @@ uc dns show [flags]
 
 ## See also
 
-* [uc dns](uc_dns.md)	 - Manage cluster domain in Uncloud DNS.
+* [uc dns](uc_dns.md)	 - Manage the cluster domain.