Add Autogenerate-config-doc code to tools

This patch brings the auto-generate-config doc tool into
the openstack-manuals repo, where it can be used to update
the configuration option tables.

patchset2 fixes obvious things noted by reviewers, likely
needs more fixing.

patchset 4 adds update feature, fixes pep8

patchset 5 removes debugging print

patchset 6 adds warning to tables regarding their
           automatically generated nature

patchset 7 updated nova flagmappings for H2 and
           adds updated nova tables

patchset 8 adds a seciton in the readme with a worked example
           from a recent use of the script

patchset 10 fixes for cinder
patchset 11 testing, fixing
patchset 12 testing, fixing
patchset 13 adds categories to cinder.flagmappings, generates
            docbook tables for cinder
patchset 14 adds mappings for neutron, and generates docbook
            tables based on these

patchset 15 adds list of bugs this patch will fix

patchset 16 fixes whitespace error in automatically generated tables :(

fixes bug 1192225
Partial-Bug 1207550
Partial-Bug 1207549
fixes bug 1206827
Partial-Bug 1206336
fixes bug 1204484
Partial-Bug 1204205
fixes bug 1202260
fixes bug 1201710
fixes bug 1200794
Partial-Bug 1200740
Partial-Bug 1200418
Partial-Bug 1200047
Partial-Bug 1199209
Partial-Bug 1197657
fixes bug 1197653
fixes bug 1197295
Partial-Bug 1197088
Partial-Bug 1195900
fixes bug 1195560
fixes bug 1195433
Partial-Bug 1192752
fixes bug 1187278
Partial-Bug 1106428
Change-Id: Icd3f4496850c375c9359a10eddb25ab5c722595e
bp:autogenerate-config-tables
Merge "Add Autogenerate-config-doc code to tools"