XWIKI-9516: Merge xwiki-platform-wiki-manager and xwiki-platform-workspace.

* Create xwiki-platform-wiki-template modules.
XWIKI-9516: Merge xwiki-platform-wiki-manager and xwiki-platform-workspace.

* Write xwiki-platform-wiki-template-api module.
XWIKI-9516: Merge xwiki-platform-wiki-manager and xwiki-platform-workspace.

* Write xwiki-platform-wiki-template-default module.
XWIKI-9516: Merge xwiki-platform-wiki-manager and xwiki-platform-workspace.

* Write xwiki-platform-wiki-template-script module.
XWIKI-9516: Merge xwiki-platform-wiki-manager and xwiki-platform-workspace.

* Create a new WikiCopier implementation.
Merge branch 'new-wiki-module' into feature-wiki-properties-group