reverse dependency between libknot and libdnssec
libdnssec reimplements lot of stuff already available in libknot (e.g., dnames, base32hex, etc.)
We should either:
- reverse the dependency, so that libknot is not dependent on libdnssec; or
- create internal (static) library with super elementary stuff, which will be used both by libknot and libdnssec.