Intents are not type safe

As we had this recently: https://github.com/nextcloud/android/pull/5857

To prevent this, my idea is to have a static "launch" function in ever needed activity, that handles creating the intent correctly.
In this case it could be:
```
public static function launch/createIntent(File file, Account account) {
Intent i = new Intent(fileActivity, ConflictsResolveActivity.class);
i.putExtra(ConflictsResolveActivity.EXTRA_FILE, file);
i.putExtra(ConflictsResolveActivity.EXTRA_ACCOUNT, account);

return i;
}
```

What do you think? @ezaquarii @AndyScherzinger