[FEATURE REQUEST] Use of alternative "remotes" instead of service accounts

[bonny1992]

Describe the problem
Since now service accounts cannot be used to get more upload quota, we can use other users in the organizations instead.
We could just create more syncers and uploaders but it'd mean a lot of Nothing to transfer after maybe a long series of checks.

Describe any solutions you think might work
In the syncer and uploader parts we could get an alternative field where we put the "alternative" remotes and if cloudplow doesn't detect an error, it will just cycle to the next syncer or uploader. Instead, if it recognizes an error, it will just proceed switching to the alternative.

...
"remotes": {
   "td-user1-test": ...
   "td-user2-test": ...
}
"syncer": {
  "sync-td-test": {
      ...
      "sync_from" : "td-user1-test",
      "alternatives": { "td-user2-test" }
}

Additional context
Ask away if more is needed!