Enable change of jitsi_meet_authentication

[tabacha]

tested with value: cyrus and value: internal_plain

For cyrus on Debian Buster you will need a backprorted version of lua-cyrussasl I dont know if we want to intergate this into the role?

[santiagomr]

For cyrus on Debian Buster you will need a backprorted version of lua-cyrussasl I dont know if we want to intergate this into the role?

For those who want to use backports on their servers, better manage them externally to a Jitsi Meet role. To indicate dependency packages to install, is already available jitsi_meet_base_packages variable

Thanks for submitting your improvements @tabacha. They're already part of the newly released v3.0.0.