Add support to delete composable index templates api to specify multiple template
names separated by a comma.
Change to cleanup template logic for rest tests to remove all composable index templates via a single delete composable index template request. This to optimize the cleanup logic. After each rest test we delete all templates. So deleting templates this via a single api call (and thus single cluster state update) saves a lot of time considering the number of rest tests.
If this pr is accepted then I will do the same change for the delete component template api.
Relates to #69973
This commit adds the initial document for version two index templates. Since these are intended to
be used in favor of V1 index templates, this re-uses the anchors for index templates to point to the
V2 APIs, renaming the V1 template docs' anchors (this was a suggestion from the docs team).
There is more documentation that can be written, but this is a start.
Relates to #53101
James Rodewig
Martijn van Groningen
debadair
Lisa Cawley
Lee Hinman
James Rodewig