Add module for colorizing nicknames to ERC

Add module for colorizing nicknames to ERC

* doc/misc/erc.texi: Add `nicks' to module lineup.
* etc/ERC-NEWS: Mention new module `nicks'.
* lisp/erc/erc-nicks.el: New file.
* lisp/erc/erc.el: (erc-modules): Add `nicks'.
* test/lisp/erc/erc-nicks-tests.el: New file.
* test/lisp/erc/erc-tests (erc-tests--modules): Add `nicks' to
inventory of available modules.  (Bug#63569)

Special thanks to Corwin Brust for doing much of the administrative
legwork to bring this addition to ERC.

Co-authored-by: Andy Stewart <lazycat.manatee@gmail.com>
Co-authored-by: F. Jason Park <jp@neverwas.me>