Kasp refactor
See https://gitlab.labs.nic.cz/labs/knot/wikis/libdnssec-refactor for what is done here.
Final resolution of keymgrs is: pykeymgr - only for importing JSON key configuration into LMDB kkeymgr - all the remaining keymgr responsibility
WIP: need to redesign KASP db to be able to handle shared key rollover.