README.md in-line with that of other osmocom CNI projects:
* markdown syntax
* link to manuals, issue tracker, gerrit contributions, etc.
Change-Id: Ieadbbe4d2963e713d569460d053460f4f99d40eb
Remove OpenSUSE bug report link, set version to @VERSION@, make it build
with CentOS 8 etc.
Related: OS#4550
Change-Id: I387b41b6c524cd3f6baad7e89b4b6b347d9998ac