Implement kea-netconf skeleton

The first programmatic step will be to implement a skeleton kea-netconf daemon. At the very minimum the code has to:

1. be able to detect sysrepo location and link with it.
2. have a standalone daemon (kea-netconf) that can accept an input config file (and do nothing with it yet)
3. the daemon must be able to log something. For the time being, printing out a version number and startup message is enough.
4. there has to be a boilerplate manual page for it.
5. there have to be unit-tests, at least one shell test and at least one gtest based test.