irc module: add validate_certs, rename use_ssl to use_tls (keeping use_ssl as an alias) (#7550)
* Rename use_ssl to use_tls, keep use_ssl as an alias.
* Add validate_certs option.
* Add changelog fragment and recommend setting TLS related settings to true.
* Fix formatting.
* Update documentation to use use_tls=true and validate_certs=true.
(cherry picked from commit f87777b9f5)
Co-authored-by: Felix Fontein <felix@fontein.de>
