Because Nodejs 16 is now LTS node, and it has various improvements
including better support for javascript modules.

We've just made the main branch as the default one.

For testing the linux app build to start with.

Any changes to the backend, frontend, makefile, etc. may influence
the image generation, so we build the image in those actions just in
case.

Use testing lib like in new create react setup.
Run frontend tests on github.
Add latest node 14.x LTS to test matrix.

New version of Go and actions@checkout are available. Add action to run
for changes in .github directory and on push to master branch event.
Signed-off-by: knrt10 <tripathi.kautilya@gmail.com>

These changes add the github actions that represent the CI system for
now.