If the user happens to create a WiMax or Wi-Fi WEP connection they get a
warning.

Run the same checks after "nmcli c modify" as we do for "nmcli c add".
That is -- warn if the resulting connection has a connection ID
collision.

We sometimes emit warnings after a connection is added. Currently
there's a warning when the connection ID collides with another one (and
a suggestion to use an UUID instead).

Let's move the check into a separate routine, so that we can reuse it
elsewhere, such as on connection "modify" (in a following commit).

Check if a connection uses something that is likely not to work --
either now or in future.

The ultimate decision on whether it's going to work is up to the daemon.
We just use the result to color the connection differently to provide
slight visual cue to the user.

Provide a visual cue suggesting that an attempt to associate with an WEP
access point might not work. Whether it actually will work up to the daemon.

This is going to be useful elsewhere. We're going to mark WEP APs as
deprecated.

Follow-up commits are going color Wi-Fi networks and connections that rely
on deprecated features differently, to provide a visual cue.

Add color definitions for those.

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1132

We have nm_device_master_add_slave(). This should be mirrored by
nm_device_master_release_slave() (not release-one-slave).

Thereby, also rename nm_device_master_release_slaves() to
nm_device_master_release_slaves_all() to make it clearer.