Further clarify networking content

Further clarify installation guide networking content to
reduce potential confusion about the purpose of each
network.

Change-Id: I1c7f79784eb80e317be1f156bc3a0e68ac39df3b
Closes-Bug: #1372669
backport: Juno
Remove defunct swift content

Remove defunct swift content in the installation guide. This
should complete the swift content improvements.

Closes-Bug: #1389382
backport: Juno
Change-Id: Iaef1c4e405859ea79bfa022cfd57905900904d0a
Imported Translations from Transifex

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

Change-Id: I3f891e25555d5c6fd390fc8c7762faf3b8b9abf6
Merge "Remove defunct swift content"
Merge "Further clarify networking content"
Imported Translations from Transifex

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

Change-Id: Id29d0d600bd1fe7120caeaa2298ad9072b3b1dc0