partman: cleanup external store profiles

Remove apache.cfg, this seems to be the old setup where application
servers were also external storage. It's unreferenced and replaced by
mw.cfg & es.cfg for the two distinct roles.

Rename es.cfg to db.cfg and discard the old db.cfg: it was
incomprehensible, unreferenced & all dbXXXX boxes seem to be configured
to be partitioned using the es.cfg profile.

Split netboot.cfg lines that use es.cfg to two, to clearly distinct
database/external boxes from misc boxes.

All of the above are non-functional changes.

Change-Id: If3a1406cd0e7730f499adf7c0f9f66ca7dc671c1