imagebuilder: add ABI suffix to packages when using apk

imagebuilder: add ABI suffix to packages when using apk

If an apk package with an ABI version doesn't have priority set, it
can't be selected by its base name:

$ make manifest PACKAGES='libustream-openssl libsqlite3'
ERROR: unable to select packages:
  libsqlite3 (virtual):
    note: please select one of the 'provided by'
          packages explicitly
    provided by: libsqlite3-0
    required by: world[libsqlite3]
  libustream-openssl (virtual):
    note: please select one of the 'provided by'
          packages explicitly
    provided by: libustream-openssl20201210
    required by: world[libustream-openssl]

Look up the ABI version in apk index and if present, add an ABI suffix
to all requested packages.

Signed-off-by: George Sapkin <george@sapk.in>
Link: https://github.com/openwrt/openwrt/pull/21449
Signed-off-by: Robert Marko <robimarko@gmail.com>