Fix issues in CI pipeline + Implement multi staged build in to two separated Images

[shakyapeiris]

I have made some changes and the purpose of this pull request is to discuss about the changes I made up to now(I'm planning to do more improvements as mentioned below).

Implemented:

• Add test step to GitHub actions
• Fixed issues with unit tests in the server/api (with jest and mongodb-memory-server)
• Separate front-end and back-end in to two Docker images (client image didn't built successfully)
• Implement multi-staged build in Images/Dockerfiles
• Update docker-compose.yml according to implemented changes in Images/Dockerfiles.
• Add Dockerfile and .dockerignore files to each respective .dockerignore files.

Future:

• Write all the tests for api
• Fix issues with the client image
• Fix issues with dependencies
• Add docker image build step to the GitHub action

Thank You
Shakya Peiris