chore(all): provider to servers map in allServers

- Simplify formatting CLI
- Simplify updater code
- Simplify filter choices for config validation
- Simplify all servers deep copying
- Custom JSON marshaling methods for `AllServers`
- Simplify provider constructor switch
- Simplify storage merging
- Simplify storage reading and extraction
- Simplify updating code

internal/configuration/settings/updater.go

@@ -43,10 +43,6 @@ func (u Updater) Validate() (err error) {
 	for i, provider := range u.Providers {
 		valid := false
 		for _, validProvider := range providers.All() {
-			if validProvider == providers.Custom {
-				continue
-			}
-
 			if provider == validProvider {
 				valid = true
 				break