legacy: bibrecord scripts move

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
legacy: fix for run_sql import in bibrecord

* Addresses issue with imports outside application context.
  (closes #2295)

* Amends imports from `invenio.legacy.bibrecord.scripts`.

Signed-off-by: Jiri Kuncar <jiri.kuncar@cern.ch>
mixer: dump database fixes

* Adds new command `inveniomanage database dump` to allow dumping the
  content of the database using the mixer.

* Fixes imports and trailing white spaces on json dump.

Signed-off-by: Esteban J. G. Gabancho <esteban.gabancho@gmail.com>