Fixes #241

[GlebMikhailov]

This MR fixes issues found in closed MR #241. In particular, the NotificationUtils class has been split, the function has been renamed from jitsiCallIntent to getCallIntent, and a new method for removing notifications from the user side - rejectNotification - has been added.

[SpiritCroc]

Note of advice, if you want to have any chance that I review this PR to maybe get it merged at some point, changes should be minimal to achieve the goal, while being as upstream-merge-friendly as possible. Currently the diff is way too huge and touches lots of upstream files. You may want to read up on #250 as well for some hints.

[GlebMikhailov]

This MR incorporates all the logic that appeared in MR #241 and includes fixes for all comments. In order to improve maintainability and readability, the NotificationsUtils class was refactored. As a result, three new classes were created: NotificationBuilderUtils, NotificationCommonUtils, and NotificationUtils. This entailed changes to a number of files related to method porting.

[GlebMikhailov]

Made changes: put all utils for jitsi into a separate class - JitsiNotificationsUtils. Went through the whole code - significantly reduced upstream issues.

Could you please take a look at this MP?

[alexander-potemkin]

Note of advice, if you want to have any chance that I review this PR to maybe get it merged at some point, changes should be minimal to achieve the goal, while being as upstream-merge-friendly as possible. Currently the diff is way too huge and touches lots of upstream files. You may want to read up on #250 as well for some hints.

Hey @SpiritCroc , Merry Christmas! :)

And thank you for checking that PR - it was me, who asked @GlebMikhailov to take over where it was left earlier, with the respect to all the comments you made earlier, to make sure the PR will be easy to accept and maintain.

I remember you do it in your free time and I understand if you will refuse it, I hope however, that there will be a way to make it all right and comfortable for you to accept - please, don't hesitate to let us know on anything that shall be adjusted 🙏🏻

[SpiritCroc]

Thanks. On first glance I thinks it looks better than the old PR. Like usual, I don't know when/if I'll have time to properly review this though.

One remark from my first look, does anybody actually need settings_labs_enable_jitsi_call_notifications_default? I think I removed it in my clean up of the old PR before but it's again here in this one. For me looks just like a useless source of merge conflicts, since we don't have the use-case that upstream has for such config resources. If it's needed for anything, should be moved into something like config-settings_sc.xml but probably best to just drop it