Update config and docs for Multiple Containers

This adds appropriate config options to reflect
changes in the Multiple Containers spec.

Approved spec:
 https://review.openstack.org/#/c/124522

DocImpact
bp: swift-store-multiple-containers
Change-Id: Ia6b4cb215c4945fb0373e9af5358725209353aa8
Adding Metadef Tag support

Adding rest api and db support for CRUD operations on the new
metadef_tags table.

Implements: https://blueprints.launchpad.net/glance/+spec/metadefs-tags
DocImpact

Change-Id: Icfa40555280ce69766381b0abe7ef399b806f6a0
Imported Translations from Transifex

For more information about this automatic import see:
https://wiki.openstack.org/wiki/Translations/Infrastructure

Change-Id: I98dbb9535b14608cfb96a2320907c6bdb68e7c8e
Merge "Update config and docs for Multiple Containers"
Merge "Adding Metadef Tag support"
Merge "Imported Translations from Transifex"