Expose sizelimit option to config generator

* Adding a group name to prevent collision with keystone
  middleware library option
* Adds an opts module for the config generator to use.
* Makes the option in sizelimit private since we don't want consumers
  using them directly.
* Moves the options to an oslo_middleware group with appropriate
  deprecated_opts settings to keep existing configs working.

Closes-Bug: #1368490
Change-Id: I72263bd363a79275a314de727a04277276866565
Fix coverage testing

Add coverage to test-requirements so that tox-e cover works - this
is part of the post jobs that are run.

Change-Id: Id919bdb861447c0f018df64d9a0f5e44c0cc2351
Support building wheels (PEP-427)

Universal is used to identify pure-Python module(by bdist_wheel). For
these, it is sufficient to build a wheel with _any_ Python ABI version
and publish that to PyPI (by whatever means).

Change-Id: I99b5c30b7d7feb00eed1c9b4c7c8a0df4e41da84
Imported Translations from Transifex

Change-Id: I99c6b951c8b6992a442b194ad480ca0418def520
Merge "Expose sizelimit option to config generator"
Merge "Support building wheels (PEP-427)"
Remove extraneous vim editor configuration comments

Change-Id: I2fb6d6174cf8b73ee663efa6718f4358be673869
Partial-Bug: #1229324