Purge deleted stacks for specific project

Add project-id argument to heat-manage purge_deleted command in order
to be able to hard delete DB entries for a specific project.

Change-Id: Idf47246a99264f5b5546812740233c06b1fd8e4b
bp:heat-manage-purge-deleted-tenant

specs/newton/heat-manage-purge-deleted-tenant.rst

@@ -0,0 +1,87 @@
+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+..
+ This template should be in ReSTructured text. The filename in the git
+ repository should match the launchpad URL, for example a URL of
+ https://blueprints.launchpad.net/heat/+spec/awesome-thing should be named
+ awesome-thing.rst .  Please do not delete any of the sections in this
+ template.  If you have nothing to say for a whole section, just write: None
+ For help with syntax, see http://sphinx-doc.org/rest.html
+ To test out your formatting, see http://www.tele3.cz/jbar/rest/rest.html
+
+=======================================================
+Enable the purge of deleted stacks for specific project
+=======================================================
+
+Add project-id argument to heat-manage purge_deleted command in order
+to be able to hard delete DB entries for a specific project.
+
+https://blueprints.launchpad.net/heat/+spec/heat-manage-purge-deleted-tenant
+
+Problem description
+===================
+
+Currently heat-manage purge_deleted command allows operators to purge
+all DB entries marked as deleted and are older than an age.
+
+Usually this global purge process is setup to run periodically in a
+cloud platform. However, for some specific projects, cloud operators
+would like to setup the purge process with much smaller retention period.
+Typical example of such project is the monitoring project that monitors
+heat service.
+
+Proposed change
+===============
+
+Add project-id argument for heat-manage purge_deleted command::
+
+  ~ # heat-manage purge_deleted --help
+  usage: heat-manage purge_deleted [-h] [-g {days,hours,minutes,seconds}]
+                                   [-p PROJECT_ID]
+                                   [age]
+
+  positional arguments:
+     age                   How long to preserve deleted data.
+
+  optional arguments:
+    -h, --help            show this help message and exit
+    -g {days,hours,minutes,seconds}, --granularity {days,hours,minutes,seconds}
+                          Granularity to use for age argument,
+                          defaults to days.
+    -p PROJECT_ID, --project-id PROJECT_ID
+                          Project ID to purge deleted stacks.
+
+When project-id argument is set, only this project DB entries marked as deleted
+will be purged. Given project-id value will not be validated, leaving
+the database unchanged if incorrect.
+
+Alternatives
+------------
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  Ala Rezmerita <ala.rezmerita@orange.com>
+
+Milestones
+----------
+
+Target Milestone for completion:
+  newton-2
+
+Work Items
+----------
+
+- Implement proposed change
+- Add the corresponding functional tests
+
+Dependencies
+============