Adding unittest - Githubissues

This PR is:

adding some unit test 30% coverage for now.
adding Makefile and a bit in Dockerfile for easy running these tests.
coverage is stet up and can be found in /out .
some refactoring of the code, jus based on logical separation of bits.
Server has a proper shutdown with closing the servers so it can be created and stopped for the tests.
README is updated contain help with verification setup.
VERSION and Changelog.md files are added.
Code is reformatted by my Goland auto formatting.

borancar / talos-pxe