Convert READMEs to markdown

[slevis-lmwg]

Description of changes

See title

Specific notes

Contributors other than yourself, if any:

CTSM Issues Fixed (include github issue #):
Fixes #2761

Are answers expected to change (and if so in what way)?
No

Any User Interface Changes (namelist or namelist defaults changes)?
No

Does this create a need to change or add documentation? Did you do so?
No

Testing performed, if any:
None needed

[slevis-lmwg]

Note to self: Look for more READMEs that need conversion.

@ekluzek how should we handle the presence of both a README and a README.md in the /ctsm directory?

[ekluzek]

@ekluzek how should we handle the presence of both a README and a README.md in the /ctsm directory?

@slevis-lmwg

Good question. The README.md shows up as what you see on github. And it's probably something we want to be short, with the main content being what we want people to see when they got to CTSM on github. In contrast, the content of the README details about how to use CTSM and some practical details about how to get around in the checkout.

So you could add the content of the plain README to the README.md, but make it at the end. The other option would be to have a file with a different name maybe something like: README_on_CTSM.md? Which sounds better to you?