docs(samples): add initial sample codes

[wuyuexin]

Thank you for opening a Pull Request! Before submitting your PR, there are a few things you can do to make sure it goes smoothly:

• Make sure to open an issue as a bug/issue before writing your code! That way we can discuss the change, evaluate designs, and agree on the general idea
• Ensure the tests and linter pass
• Code coverage does not decrease (if any source code was changed)
• Appropriate docs were updated (if necessary)

Fixes #12 🦕

[kurtisvg]

This region tag should be above the run_sample function

[kurtisvg]

@busunkim96 I don't see any Kokoro tests running on this repo. Is that intentional?

[busunkim96]

@kurtisvg Kokoro isn't running is because author is outside the org. I also need to add samples configs though. Opened 334490453.

[kurtisvg]

@kurtisvg Kokoro isn't running is because author is outside the org. I also need to add samples configs though. Opened 334490453.

That was specifically what I was referring too :)

[kurtisvg]

@wuyuexin Let me know if you need help merging this.

[wuyuexin]

@wuyuexin Let me know if you need help merging this.

Yes, I'm not familiar with the merging process. Is there anything I need to do?

[busunkim96]

👋 There's a small tweak I want to make to the noxfile/noxfile_config. I'll merge it for you right after that @wuyuexin.

Side note, I think I'll have to add another PR template for samples that looks like the one in python-docs-samples.