Fix/lock lowdb file (#470)

* Lock data.json while running

* Await floating promises

* Increase retry frequency and attempt count for lock file

* tweak lock retry times

src/commands/unlock.command.ts

@@ -67,7 +67,7 @@ export class UnlockCommand {
       }
     }
 
-    this.setNewSessionKey();
+    await this.setNewSessionKey();
     const email = await this.stateService.getEmail();
     const kdf = await this.stateService.getKdfType();
     const kdfIterations = await this.stateService.getKdfIterations();