Quotient::NAM doesn't retry on errors

[KitsuneRal]

CI status for libQuotient is downright useless because of one test sporadically failing, most likely due to ~~429 Too Many Requests~~ "Internal server error" returned to Quotient::NAM that doesn't know how to handle it (BaseJob-backed requests would retry on it). This failure is not exactly bogus - it basically indicates that requests issued directly to NAM (e.g. those coming from QML directly, rather than via image providers) will sometimes equally fail in real usage.

To fix this, code that handles retries has to be moved from BaseJob and ConnectionData to NAM instead.