Include screening examples in doc

[rwxayheee]

Hi, I just pushed the Colab examples to readthedoc.
https://meeko.readthedocs.io/en/readthedocs/colab_examples.html

There are currently 6 examples (4 Vina + 2 AD-GPU). Each is one single-docking experiment. The procedure is slightly different but the general workflow is the same.

• These examples may need some final touch to be up to date with the recent changes we made to the command line scripts.

Specifically:

• Syntax change & a brief explanation (-o -v -g -j)
• Branch: use release when we have the next one

The updates will be made directly on the linked notebook. Therefore, it's safe to merge before we finalize the notebook contents.

• I'm adding 1-2 more screening examples in future.

I have a plan but I haven't started writing them yet, so I don't have an ETA... They will use AD-GPU and involve post-processing by Ringtail. And a different workflow picture.

[rwxayheee]

Merged #354. The existing notebooks and published tutorials for Vina & meek are up to date with the current release (v0.6.0). Will start task 2 after some revision of the rsd3 website