refact(cmd): Encapsulate some functionality on Command and Server

This commit extracts 3 separate pieces of functionality into their own
function/method:

- Extracts the database opening with the intention to have a function
  that performs all that functionality but returns the created database
  object rather than setting it to the Server structure.
- Extracts database validation logic, to provide a common code path for
  upcoming functionality.
- Expose schema manager on the Command struct as well as providing
  common functions to acquire shared lock/close.

internal/cmd/base/dev.go

@@ -93,7 +93,7 @@ func (b *Server) CreateDevDatabase(ctx context.Context, opt ...Option) error {
 		b.Info["dev database container"] = strings.TrimPrefix(container, "/")
 	}
 
-	if err := b.ConnectToDatabase(ctx, dialect); err != nil {
+	if err := b.OpenAndSetServerDatabase(ctx, dialect); err != nil {
 		if c != nil {
 			err = multierror.Append(err, c())
 		}