There's /usr/share/qt5/translations/ now too, handle that.

OTOH we've got some CJK support already, time to split up
those "cleanups" into some target locale set dependent form.

The features might get copy-pasted (or even copied-and-pruned)
when initialized; there's an unneccessary duplication of the
function name in the line adding it to FEATURES list, thus
prone to being forgotten and causing some havoc later on.

It was wrong in the first place but tackling this with some
double-colon rules ran into terminality issues, and further
tortures were considered unneccessary.

The current solution isn't perfect (no completely transparent
function name registration upon corresponding target being called)
but at least it is an improvement...

install2 cleanups:

- functionally indifferent ones: particularly, install2/*/98system's
  "mkdir -p /image" was superfluous as it was done by that time already
  by sub.in/stage2/image-scripts.d/00stage1

- taken apart, prepared for tags: so far it's a mostly moot change
  since the installer cleanup scripts themselves are mostly the same as
  preceding 90cleanup was (with some additions corresponding to recent
  kernel development); it's still unclear what the mechanism for
  configuring the cleanups in effect will be, either directory/package
  regex lists or tagged scripts excluded from execution by yet another tag

fixes:

- image.in/Makefile: fix metadata related test; the actual test was
  assuming that stage1 kernel means installer, which is not the case
  since generic stage2 introduction; oh well

- 85cleanup-lowmem: a "_" too much was the culprit in destroying the
  needed translations along with those deemed superfluous; thanks go to
  Oleg Ivanov and Lenar Shakirov for finding the bug and proposing the
  fix altogether

additions:

- features.in/Makefile: reworked help target; it was rather inaccessible
  due to BUILDDIR normally undefined at the time of direct make
  invocation, and BUILDDIR is normally defined during normal builds
  anyways so let's try it this way.

- README++

daydreams:

- 01-genbasedir: we should drop bzip2 compressed pkglists some day
  but see genbasedir and apt-cdrom first, 90-pkg.sh (alterator-pkg)
  will fail miserably otherwise

(these *really* should be added atomically with the changes!)

- introduced generic stage2 subprofile (non-standalone)
- ported installer and rescue over to stage2/{install2,rescue}
- initial stage2/live (needs more work for sure)
- use make-initrd-propagator
- updated and somewhat extended doc/

NB: mind #26133, #26134

This feature should absorb ha^Wmeasures for keeping install2
memory footprint to minimum, and so far it drops things not
critical for ru/uk/be users on the floor.

Should be ported to a l10n support framework when there's one.