Fix External ID not set during DC Sync

[BlackDex]

While working on the fix for #3777 I realized the location where the external_id
is stored was wrong. It was stored in the users table, but it actually
should have been stored in the users_organizations table.

This will move the column to the right table. It will not move the
values of the external_id column, because if there are more
organizations, there is no way to really know which organization it is
linked to. Setups using the Directory Connector can clear the sync
cache, and sync again, that will store all the external_id values at
the right location.

Also changed the function to revoke,restore an org-user and set_external_id to return a boolean.
It will state if the value has been changed or not, and if not, we can
prevent a save call to the database.

The users table is not changed to remove the external_id column, thi
to prevent issue when users want to revert back to an earlier version
for some reason. We can do this after a few minor release i think.

Fixes #3777

[BlackDex]

Converted to a draft. I have the code fixed, but i need to do the SQL migrations and testing before this can be merged.

I'm moving the external_id into the user_org table.

[BlackDex]

The only thing i encountered is, that you can't revert back that easily after this PR has been merged to a previous version.
The reason is we have removed a column from the users table which causes an issue with older versions.

This makes me wonder what we should do here?
Leave the column there for a while, and create some tech-debt ticket/todo to remove it in the future say, x new minor release, or x date or something?

@dani-garcia what do you think?

[stefan0xC]

Since we in general don't support downgrading I think we could remove the column the next release after the release with this PR (so if there should be an issue they can roll back to the latest working release). Provided that the next release fixes the armv6 issue which currently compels users to downgrade back to 1.29.1. Otherwise we should probably delay removing the column for another release (or warn affected users to use the -alpine images images instead because downgrading to a previous version - especially one without this change - might require a manual restore of the column).

[BlackDex]

I agree, lets remove the deletion of the column for now.