Add v2 Manila API path as base for microversions

To prevent a microversioned client from managing a non-microversioned
Manila server, Manila must update its REST endpoints by adding /v2 for
all microversioned APIs.

This commit does the following:

* Add /v2 to the URL map, connected to all the same /v1 API methods
* Renumber the microversion sequence starting from 2.0
* Update the versions API to reflect v2
* Publish the new endpoint to Keystone in the DevStack plug-in
* Update relevant documentation
* Update Tempest tests for microversions
APIImpact
Co-Authored-By: Andrew Kerr <andrew.kerr@netapp.com>
Closes-Bug: 1488624
Change-Id: I56a516b5f81914557dd2465746629431cfd6deac
diff --git a/manila_tempest_tests/config.py b/manila_tempest_tests/config.py
index 046f8cd..daed82e 100644
--- a/manila_tempest_tests/config.py
+++ b/manila_tempest_tests/config.py
@@ -32,11 +32,11 @@
 
 ShareGroup = [
     cfg.StrOpt("min_api_microversion",
-               default="1.0",
+               default="2.0",
                help="The minimum api microversion is configured to be the "
                     "value of the minimum microversion supported by Manila."),
     cfg.StrOpt("max_api_microversion",
-               default="1.6",
+               default="2.5",
                help="The maximum api microversion is configured to be the "
                     "value of the latest microversion supported by Manila."),
     cfg.StrOpt("region",