CLI: Use the new DELETE project endpoint

See the description for https://app.clickup.com/t/861nayppe and https://app.clickup.com/t/861nayqwz and mimic the same in the py-client/plugin.

The existing remove CLI function:

• should use the POST v2/project/{id}/scheduleDelete by default and returns when the project will be deleted
• should have a new flag -f, --force-delete to remove the project immediately by calling DELETE /project/{id}

Also, add a help text to that CLI function explaining that normal remove will schedule the project for deletion and the force will remove it forever immediately.

In autotests, use the new version (immediate delete) when doing cleanup.

Comments
Martin D: immediate removal of projects added to python API: https://github.com/MerginMaps/mergin-py-client/pull/177
Martin D: For the time being, clients still use the "old" v1 delete endpoint - we should switch to the v2 delete endpoint only after some time when also CE/EE servers are likely to be migrated already...

Migrated from: https://app.clickup.com/t/861nayu2h

從 py-client/plugin 中現有的 remove CLI 函式以及清理專案的 autotests 開始。將其目前的刪除請求與 v2 scheduleDelete 和立即 DELETE 端點進行比較，然後透過相關測試驗證說明文字、force-delete 選項、返回的排程資訊以及清理行為。