Add support for libayatana-appindicator library to telega-server

[jumper047]

Ubuntu 22 drops support of the libappindicator library in prior to libayatana-appindicator. It still has libappindicator in it's repo, but ubuntu-desktop package depends on ayatana version, so user can't just install libappindicator. You can check some background here - AyatanaIndicators/libayatana-appindicator#30 (comment).

Luckily, libayatana-appindicator interface is identical to libappindicator, so I added some additional ifs to use any of those libraries with telega-appindicator.

[zevlg]

Thanks, but could you please revert changes to doc/ folder. In some future we will get documentation things fully automated. Also, does etc/Dockerfile also requires that new appindicator library?

[jumper047]

revert changes to doc/

done

does etc/Dockerfile also requires that new appindicator library?

I'll try to test it - if I understand it right, telega-server manipulates tray icon via appindicator library inside container. If this statement is correct , then, maybe, it's worth to update it because new library is maintained by community and old one - not.

[zevlg]

Merged in, thank you for the contribution!