Ensures that long-running HTTP requests, such as downloads and uploads, do not timeout prematurely.
This change configures specific HttpClient instances with an infinite timeout to accommodate operations that may take an extended period. The default 100s timeout is retained for some operations like registration, where a long delay may indicate a problem.
This PR moves the check from the FTP backend into shared code, so all backends will now check for read/write permissions when using the "Test" button.
For situations where write permissions are not required (like restore or verify) there is a flag on the v2 API that indicates if the connection was established, so the UI can show a message suggesting that it is possible to proceed, if the current UI operation does not require write permissions.
This fixes#2473
Marcelo C.