Properly sets up the mistral-extra repository with packaging and testing
setup, in order to add gating in CI.
Change-Id: I204745785e63cc8b1ae47da5cc59eda6da18b722
Depends-On: I5e75914e500837babdeb358a76ec7d90c56f61ac
* "examples" file tree should not be Python packages
* Examples should have their own dependencies, if needed, not centralized
Next steps:
* Prepare a layout for storing OpenStack actions
Depends-on: Id8e5d55e34ec3b3d555b5482e13f99c2561e871e
Partially implements: blueprint mistral-custom-actions-api
Change-Id: Ic5b0f655686361ee00bdb70ea13bc66ce0769f90