Initialize unit testing and code coverage

* add: vitest configs

* added vitest scripts to package

* test coverage of src code

* initial unit testing

* added new testing workflows

* comments added, overlapping tests removed

* decouple env, tests

---------

Co-authored-by: Kevin Dang <kevinthedang_1@outlook.com>

tests/mentionClean.test.ts

@@ -0,0 +1,17 @@
+import { describe, expect, it } from 'vitest'
+import { clean } from '../src/utils/mentionClean'
+import { getEnvVar } from '../src/utils'
+
+/**
+ * MentionClean test suite, tests the clean function
+ * 
+ * @param name name of the test suite
+ * @param fn function holding tests to run
+ */
+describe('#clean', () => {
+    // test for id removal from message
+    it('removes the mention from a message', () => {
+        const message = `<@${getEnvVar('CLIENT_UID')}> Hello, World!`
+        expect(clean(message)).toBe('Hello, World!')
+    })
+})