Split up the base_parser function

The goal of breaking apart the base_parser() function is to get rid of
a bunch of conditionals and parameters in the code and, instead, make
code look like simple composition.

When splitting, a choice had to be made as to whether this would operate
by side effect (modifying a passed in parser) or side effect-free
(returning a new parser everytime).

Making a version that's side-effect-free appears to be fighting with the
optparse API (it wants to work by creating a parser object, configuring
the object, and then parsing the arguments with it) so instead, make it
clear that our helper functions are modifying the passed in parser by
(1) not returning the parser and (2) changing the function names to be
more clear that it is operating by side-effect.

Also move all of the generic optparse code, along with the argument
context classes, into a new subdirectory.

lib/ansible/cli/galaxy.py

@@ -14,8 +14,9 @@ import yaml
 
 from jinja2 import Environment, FileSystemLoader
 
-from ansible import context
 import ansible.constants as C
+from ansible import context
+from ansible.arguments import optparse_helpers as opt_help
 from ansible.cli import CLI
 from ansible.errors import AnsibleError, AnsibleOptionsError
 from ansible.galaxy import Galaxy
@@ -109,7 +110,7 @@ class GalaxyCLI(CLI):
         if self.action not in ("delete", "import", "init", "login", "setup"):
             # NOTE: while the option type=str, the default is a list, and the
             # callback will set the value to a list.
-            self.parser.add_option('-p', '--roles-path', dest='roles_path', action="callback", callback=CLI.unfrack_paths, default=C.DEFAULT_ROLES_PATH,
+            self.parser.add_option('-p', '--roles-path', dest='roles_path', action="callback", callback=opt_help.unfrack_paths, default=C.DEFAULT_ROLES_PATH,
                                    help='The path to the directory containing your roles. The default is the roles_path configured in your ansible.cfg'
                                         ' file (/etc/ansible/roles if not configured)', type='str')
         if self.action in ("init", "install"):
@@ -118,7 +119,7 @@ class GalaxyCLI(CLI):
     def init_parser(self):
         ''' create an options parser for bin/ansible '''
 
-        self.parser = super(GalaxyCLI, self).init_parser(
+        super(GalaxyCLI, self).init_parser(
             usage="usage: %%prog [%s] [--help] [options] ..." % "|".join(sorted(self.VALID_ACTIONS)),
             epilog="\nSee '%s <command> --help' for more information on a specific command.\n\n" % os.path.basename(sys.argv[0]),
             desc="Perform various Role related operations.",
@@ -130,8 +131,6 @@ class GalaxyCLI(CLI):
                                help='Ignore SSL certificate validation errors.')
         self.set_action()
 
-        return self.parser
-
     def post_process_args(self, options, args):
         options, args = super(GalaxyCLI, self).post_process_args(options, args)
         display.verbosity = options.verbosity