GODT-1381: Use in-memory cache in case local cache is unavailable

- change: refactor GUI notification object
- add: global bridge errors
- add: when cache on disk cannot be initialized fallback to memory cache
- add: show notification for CoD failure
- change: do not allow login to IMAP and SMTP when CoD init failed

internal/imap/bridge.go

@@ -30,6 +30,7 @@ type cacheProvider interface {
 
 type bridger interface {
 	GetUser(query string) (bridgeUser, error)
+	HasError(err error) bool
 }
 
 type bridgeUser interface {