Resolve deprecated iOS functions, lint fixes

[alexookah]

In this MR, I resolved all deprecated functions for Capacitor 3.0 in iOS.
Also fixed some minor lint fixes (removing ;)
Hope someone else will handle also the android changes

[alexookah]

I am not really sure for the change:
call.save() if it should really be changed to call.keepAlive = yes.
Maybe this https://capacitorjs.com/docs/core-apis/saving-calls helps verify my change?

[baumblatt]

Hi @alexookah ,

First of all, great work here, congrats.

The version 3.1.2-rc.0 with your changes is out there under tag next.

Everything works fine here, looking forward to hearing of your tests.

I will take a look at android platform as soon as possible.

Best regards.