Store envelope actions in a debounced queue

Is your feature request related to a problem? Please describe.

Let's say I delete multiple envelopes in rapid succession one-by-one. This would cause many small requests to be sent to the backend which cause a lot of unnecessary connection to the IMAP server. Operations should be bundled in larger chunks.

Requires https://github.com/nextcloud/mail/pull/10280

Describe the solution you'd like

Implement an envelope action queue in the frontend. Have a debounced flush timer that sends all similar actions in one big chunk to the backend, e.g. wait for a second without interaction and send all deletes at once.

Describe alternatives you've considered

No response

Additional context

This require extensive refactoring of our frontend. An action queue probably means to have a good abstraction over all possible envelope actions that have to be stored centrally. We would also need to think about handling errors (rollbacks?).

Start by reviewing required pull request #10280, then trace the frontend paths that send envelope actions. The issue names no files or tests, so map where these actions are coordinated before designing the queue. Done means similar rapid actions are bundled after the debounce period and the error or rollback behavior is resolved.