Add SQL table and index definitions for a new renameuser_queue table
that will be used to store new requests, back a request processing tool
for stewards and block new account registrations from taking a name that
pending approval as a rename.

Which wikis are affected:

• All (indirectly)

Which tables:

• centralauth.renameuser_queue

What is the change to those tables:

• new table
• three new indices

Links to gerrit changes and/or other related bug reports.

• https://gerrit.wikimedia.org/r/#/c/150997/
• https://bugzilla.wikimedia.org/show_bug.cgi?id=68889
• https://bugzilla.wikimedia.org/show_bug.cgi?id=68886

Version: unspecified
Severity: normal