[MM-22102] upgrade to electron 7 (#1268)

* fix errors

* upgrade to electron 7

* getsavepath is deprecated

* fix typo

* disable messaging from 'null'

* replace getname to its property

* deprecated zoomlevel

* deprecated setbadgecount

* isdarkmode deprecated

* it's a property, not a function

* fix error message

* fix test

* fix test on linux

test/specs/browser/settings_test.js

@@ -78,6 +78,7 @@ describe('browser/settings.html', function desc() {
         click('#addNewServer').
         waitForVisible('#newServerModal').
         setValue('#teamNameInput', 'TestTeam').
+        pause(100).
         setValue('#teamUrlInput', 'http://example.org').
         click('#saveNewServerModal').
         waitForVisible('#newServerModal', true).