logger: Add channel-based filtering.

logger: Add channel-based filtering.

This adds the ability to filter console
logging by channel or groups of channels.
This can be useful on busy systems where
an administrator would like to analyze certain
calls in detail. A dialplan function is also
included for the purpose of assigning a channel
to a group (e.g. by tenant, or some other metric).

ASTERISK-30483 #close

Resolves: #242

UserNote: The console log can now be filtered by
channels or groups of channels, using the
logger filter CLI commands.