so far it only lists installed packages

This reverts commit b852d670.

Each dep is separated with a single space. I.E:

D:dep1 dep2 dep3

Defaults to /etc/apk/repositories, absolute path and not relative
the install root.

Make the db of installed packages more similar to index file and
reuse the code. Also rename the database file.

Checksum of installed is computed on the fly when extracting them
and it'll be saved to fdb. When installing config files those are
diverted with suffix .apk-new if earlier version of same file with
local changes exist.

They are replaced by abuild now.