rename README to README.md

The filename needs the proper extension for GitLab to handle
the file as a Markdown file.

Fix some style issues so that the file renders correctly.

Signed-off-by: Jakub Janků <jjanku@redhat.com>
2 jobs for misc-fixes in 6 minutes and 17 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #310115
build

00:03:19

passed #310116
build_win

00:06:17