chore: do not use sentinel errors when unneeded

- main reason being it's a burden to always define sentinel errors at global scope, wrap them with `%w` instead of using a string directly
- only use sentinel errors when it has to be checked using `errors.Is`
- replace all usage of these sentinel errors in `fmt.Errorf` with direct strings that were in the sentinel error
- exclude the sentinel error definition requirement from .golangci.yml
- update unit tests to use ContainersError instead of ErrorIs so it stays as a "not a change detector test" without requiring a sentinel error

internal/configuration/settings/server.go

@@ -46,8 +46,7 @@ func (c ControlServer) validate() (err error) {
 	uid := os.Getuid()
 	const maxPrivilegedPort = 1023
 	if uid != 0 && port != 0 && port <= maxPrivilegedPort {
-		return fmt.Errorf("%w: %d when running with user ID %d",
-			ErrControlServerPrivilegedPort, port, uid)
+		return fmt.Errorf("cannot use privileged port without running as root: %d when running with user ID %d", port, uid)
 	}
 
 	jsonDecoder := json.NewDecoder(bytes.NewBufferString(c.AuthDefaultRole))