Add event return capability to Splunk returner

[mymindstorm]

What does this PR do?

Adds event_returner support to Splunk returner.

I've tested this patch against my company's Splunk environment.

What issues does this PR fix or reference?

References: #50815

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

Commits signed with GPG?

Yes

[mymindstorm]

@dhiltonp is there anything I can do to help get this PR reviewed?

[github-actions]

Hi! I'm your friendly PR bot!

You might be wondering what I'm doing commenting here on your PR.

Yes, as a matter of fact, I am...

I'm just here to help us improve the documentation. I can't respond to
questions or anything, but what I can do, I do well!

Okay... so what do you do?

I detect modules that are missing docstrings or "CLI Example" on existing docstrings!
When I was created we had a lot of these. The documentation for these
modules need some love and attention to make Salt better for our users.

So what does that have to do with my PR?

I noticed that in this PR there are some files changed that have some of these
issues. So I'm leaving this comment to let you know your options.

Okay, what are they?

Well, my favorite, is that since you were making changes here I'm hoping that
you would be the most familiar with this module and be able to add some other
examples or fix any of the reported issues.

If I can, then what?

Well, you can either add them to this PR or add them to another PR. Either way is fine!

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Whatever approach you decide to take, just drop a comment here letting us know!

Detected Issues (click me)

[INFO] Initializing environment for https://github.com/saltstack/pip-tools-compile-impersonate.
[INFO] Initializing environment for https://github.com/asottile/pyupgrade.
[INFO] Initializing environment for https://github.com/saltstack/pre-commit-remove-import-headers.
[INFO] Initializing environment for https://github.com/s0undt3ch/salt-rewrite.
[INFO] Initializing environment for https://github.com/timothycrosley/isort.
[INFO] Initializing environment for https://github.com/timothycrosley/isort:toml.
[INFO] Initializing environment for https://github.com/psf/black.
[INFO] Initializing environment for https://github.com/asottile/blacken-docs.
[INFO] Initializing environment for https://github.com/asottile/blacken-docs:black==21.7b0.
[INFO] Initializing environment for https://github.com/PyCQA/bandit.
[INFO] Initializing environment for https://github.com/saltstack/invoke-pre-commit.
[INFO] Initializing environment for https://github.com/saltstack/invoke-pre-commit:blessings,distro,jinja2,msgpack,pyyaml.
[INFO] Initializing environment for https://github.com/saltstack/mirrors-nox.
[INFO] Initializing environment for https://github.com/saltstack/mirrors-nox:pip>=20.2.4,<21.2,setuptools<58.0.
[INFO] Installing environment for https://github.com/saltstack/invoke-pre-commit.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
Check Known Missing Docstrings...........................................Passed
- hook id: invoke
- duration: 1.08s

---

Thanks again!

[dhiltonp]

re-run pr-fedora-35-x86_64-py3-pytest

[dhiltonp]

@s0undt3ch I've re-run the failing test 2 or 3 times, do you have an idea what's up with it?

[mymindstorm]

re-run pr-centos-7-x86_64-py3-m2crypto-pytest
re-run pr-arch-lts-x86_64-py3-pytest
re-run pr-amazon-2-x86_64-py3-pytest
re-run pr-alma-8-x86_64-py3-pytest

[mymindstorm]

I updated the branch and some of the CI seems to be failing due to some problem communicating with AWS. Re-running...

[mymindstorm]

@dhiltonp the CI issues with this PR appear to be resolved.