Redundant given this is the project-wide license already,
especially in file headers that already include the GPL license
header.
This and other minor fixups based on feedback from Ie0cea0ef5027c7e5.
* Add @file where missing.
* Move @ingroup and @deprecated from file to class doc where needed.
Change-Id: I7067abb7abee1f0c238cb2536e16192e946d8daa
This moves and refactors the ConsistentReadConnectionManager
from Wikibase into the core rdbms lib.
The refactoring also creates a generic ConnectionManager.
This relates to Iff20a22f9f2bc7ceefd6defc0ed9a494a6fe62c0
which introduced a DB factory / connection manager in
an extension revealing the need for this in multiple places.
Change-Id: I0c58e15aed5bed88323d18cb95e5008f8d3381c5
