Extend service.enabled() to accept kwargs

This can be used to create stronger checks on the 'enabled' status of a
service. For example, if the service is enabled with the proper flags.
Consolidating the _get_options function from all the returners that were using it into the config module.  Additionally some cleanup and ability to pass defaults to the get_returner_options function.

fixing lint issues

moving the get_options function into a utils.py under returners.  previous attempt at using a call to the salt config module doesn't work if the returner is called from the scheduler.

adding missing docstring

Unit tests were failing for SMTP returner because __opts__ was not available.  Ensuring it's available, empty, if it doesn't already exist.

removing the check and population with an empty dict for __salt__ and __opts__.  Adding an empty __opts__ to the smtp returner unit tests.
Moving the get_options function into the __init__.py instead of utils.py.
salt/utils/process.py: fix order of args to os.kill()

Fixes: #15269
Signed-off-by: Dan Mick <dan.mick@inktank.com>
Fixing sphinx errors and violations
More sphinx errors and violations
Fixing more sphinx errors and violations
Fix salt.modules.mount.active to use /proc/self/mounts, unless user explicitly enabled use of /proc/self/mountinfo via extended=True option. Fix remount on every state application, when options that don't appear in /proc/self/mounts are used.
BUG: Fix for result in states.file.prepend to return the correct result when test option is set (see issue #15397)
Add libcloud dependency notice to provider docs
Remove unnecessary import requirements to cloud integration tests
ENH: Added functionality to expand user variables in paths for the salt module/state file module
ENH: Added list_upgrades and upgrade_available to modules.pip
openbsdrcctl: extend enabled() to check flags

On OpenBSD, it's possible to define particular flags a daemon should be
enabled with (ala /etc/sysconfig/... in RedHat). To make sure the flags
are properly updated when changed (in pillars or states), we return a
service as "disabled" if the currently configured flags do not match the
provided ones; this ensures /etc/rc.conf.local is always in sync.
Merge pull request #15506 from rallytime/document_libcloud_reqs

Update cloud driver docs with/without libcloud deps
tests: recognize OpenBSD
Adding optional tag functionality to salt.modules.dockerio.push
Adding optional tag in salt.states.dockerio.pushed
Minor doc change
Merge pull request #15462 from garethgreenaway/returner_experiments

Updates to returners, consolidated code.