Add xstatic and xstatic-jquery for Horizon

We are unbundling the static JS files from Horizon, moving them
to separate packages where possible. That means, that we have to
depend on those packages in requirements now.

This is for the patch https://review.openstack.org/#/c/82516/

Both xstatic and xstatic-jquery are not yet packaged in Ubuntu or
Fedora, but are used by at least one other large project, MoinMoin 2.

Change-Id: Iac5b5baf9d46c8deffd51d8b33345f7e21a50126
Partial-implements: blueprint https://blueprints.launchpad.net/horizon/+spec/remove-javascript-bundling
Fix whitespace that occurs after comma

Use a custom tuple of separators for json.dumps that avoids
having the comma+space, which looks bad if this is ever committed.
Replace it by just having ": " and "," (no space after) instead.

An example of this so that it can be more clear:

http://paste.openstack.org/show/84238/

Note the above paste where the old version has spaces after
commas where as the newer version does not have these spaces.

Change-Id: Ifd04d5e1b26ebdf9db374761f31baaf1e33d87cd
Bump minimum oslo.config version to 1.2.1

oslo.config-1.2.1 has a required fix for interaction
with argparse, which effects trove and glance at least.
Related patch: I8d1b52e5390295726eb49af32eb7cab14c29592c

Change-Id: Icf7fa53834ddbd5a480984da9dbc39a207005b21
Merge "Fix whitespace that occurs after comma"
Merge "Bump minimum oslo.config version to 1.2.1"