Implement a framework for having common code for release scripts (#55893)

* Implement a framework for having common code for release scripts

* Release scripts will go through hacking/build-ansible.  build-ansible is
  a pluggable script which will set a directory that has common code for
  non-enduser scripts.  It will then invoke the plugin which implements
  that subcommand.  Uses straight.plugin for loading each sub-command.

* We're going to add tools which are needed to test ansible (the changelog
  generation, for instance) so we need to include the pieces relevant to
  that in the tarball.

* Add straight.plugin to the sanity test requirements for the same
  reason

* Skip compile test just for build-ansible plugins which won't be run as
  part of sanity tests.

hacking/build_library/build_ansible/commands.py

@@ -0,0 +1,50 @@
+# coding: utf-8
+# Copyright: (c) 2019, Ansible Project
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+# Make coding more python3-ish
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+
+from abc import ABCMeta, abstractmethod, abstractproperty
+
+
+class Command:
+    """
+    Subcommands of :program:`build-ansible`.
+
+    This defines an interface that all subcommands must conform to.  :program:`build-ansible` will
+    require that these things are present in order to proceed.
+    """
+    @staticmethod
+    @abstractproperty
+    def name():
+        """Name of the command.  The same as the string is invoked with"""
+
+    @staticmethod
+    @abstractmethod
+    def init_parser(add_parser):
+        """
+        Initialize and register an argparse ArgumentParser
+
+        :arg add_parser: function which creates an ArgumentParser for the main program.
+
+        Implementations should first create an ArgumentParser using `add_parser` and then populate
+        it with the command line arguments that are needed.
+
+        .. seealso:
+            `add_parser` information in the :py:meth:`ArgumentParser.add_subparsers` documentation.
+        """
+
+    @staticmethod
+    @abstractmethod
+    def main(arguments):
+        """
+        Run the command
+
+        :arg arguments: The **parsed** command line args
+
+        This is the Command's entrypoint.  The command line args are already parsed but from here
+        on, the command can do its work.
+        """