implement testing and add code coverage

[mcsamuelshoko]

• [x] Install jest for typescript into the project.
• [ ] Add codecov to repo as a code coverage tool
• [ ] Add codecov badge

[mcsamuelshoko]

• jest has been installed but is having an error when run :

SyntaxError: /home/user/Documents/GitHub/mcsamuel.github.io/tsconfig.json: Expected property name or '}' in JSON at position 29
    at parse (<anonymous>)
    at Module._extensions..json (node:internal/modules/cjs/loader:1315:39)
    at Module.load (node:internal/modules/cjs/loader:1103:32)
    at Module._load (node:internal/modules/cjs/loader:942:12)
    at Module.require (node:internal/modules/cjs/loader:1127:19)
    at require (node:internal/modules/helpers:112:18)
    at Object.<anonymous> (/home/mcsamuel/Documents/GitHub/mcsamuel.github.io/jest.config.js:1:29)
    at Module._compile (node:internal/modules/cjs/loader:1246:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1300:10)
    at Module.load (node:internal/modules/cjs/loader:1103:32)