[MM-40406] Add more singletons, refactor main.ts into pieces, add tests and some cleanup + tests for additional coverage (#1890)

* Refactor main.ts dependencies into singleton pattern

* Split main.ts into testable pieces, some other refactoring for singleton pattern

* Unit tests for main/app/app

* Unit tests for main/app/config

* Unit tests for main/app/initialize

* Unit tests for main/app/intercom

* Unit tests for main/app/utils

* Add some more tests to get to 70% coverage

* Fix for linux

* Fix for alternate data dir paths

* Fix E2E test

package.json

@@ -72,10 +72,15 @@
       "jsx",
       "json"
     ],
+    "collectCoverageFrom": [
+      "src/common/**/*.ts",
+      "src/main/**/*.ts"
+    ],
     "testMatch": ["**/src/**/*.test.js"],
     "globals": {
       "__HASH_VERSION__": "5.0.0"
-    }
+    },
+    "setupFiles": ["./src/jestSetup.js"]
   },
   "devDependencies": {
     "@babel/cli": "^7.14.5",