[enhancement] Automatized build, DMG and Notarization

[EETagent]

Continuation of the discussion from #40

TLDR: It would be great to have fully automatized build procedure with .app and .dmg sign, notarization and release.

What we have so far:

• [x] Build .app
• [x] Sign .app
• [x] Package .dmg
• [x] Release .dmg
• [x] Get commit messages since last tag and post them as a release description ( not merged currently )

Paid certificate is needed so this won't be implemented:

• [ ] Sign .dmg
• [ ] Notarize .app
• [ ] Notarize .dmg

Possibly in the future:

[?] Generate AppCast.xml #26

Currently untested release.yml

Notarization is requirement for secure app distribution outside of ( and in ) an App Store. Without it ( Since Catalina ), user would see unknown developer warning and would have to manually allow first app launch through preferences ( Does not affect machines where is Gatekeeper disabled sudo spctl --master-disable ).

[MSzturc]

That's bad. Im not able to reproduce this error. I guess since since my certificate is in my keychain it detects that it's my own software and starts without this error..

[MSzturc]

Aww.. i've noticed that a paid account is needed for the notarize program, my free developer account is not enough. This account costs 99$ a year.

[EETagent]

Oh, I thought you have a paid cert. Sorry, we can skip that then.

[EETagent]

@MSzturc

I removed all notarization things. There is still .app signature check though