feat(caddy): add ListCertificates method, refactor Caddy client layout (#31)

go.mod

@@ -34,6 +34,7 @@ require (
 	github.com/google/uuid v1.6.0
 	github.com/jmoiron/sqlx v1.4.0
 	github.com/mattn/go-shellwords v1.0.12
+	github.com/mholt/acmez/v3 v3.1.6
 	github.com/miekg/dns v1.1.73
 	github.com/mitchellh/mapstructure v1.5.0
 	github.com/moby/term v0.5.2
@@ -178,7 +179,6 @@ require (
 	github.com/mdlayher/netlink v1.7.2 // indirect
 	github.com/mdlayher/socket v0.5.1 // indirect
 	github.com/mgutz/ansi v0.0.0-20200706080929-d51e80ef957d // indirect
-	github.com/mholt/acmez/v3 v3.1.6 // indirect
 	github.com/miekg/pkcs11 v1.1.2 // indirect
 	github.com/mitchellh/go-homedir v1.1.0 // indirect
 	github.com/mitchellh/hashstructure/v2 v2.0.2 // indirect