Fix #760, Expand cmake documentation

[astrogeco]

Describe the contribution

Expands cmake documentation

Testing performed
Documentation-only, just proofreading

Expected behavior changes
None

System(s) tested on
n/a

Additional context
none

Third party code
none

Contributor Info - All information REQUIRED for consideration of pull request
Gerardo E. Cruz-Ortiz, NASA
Elizabeth Timmons (@ejtimmon), NASA

[skliper]

I recommend we avoid duplication of implementation information in the README. If instead the README referenced where things are documented or implemented there's less chance of things getting out of sync. Single source of truth preferred.

[astrogeco]

I recommend we avoid duplication of implementation information in the README. If instead the README referenced where things are documented or implemented there's less chance of things getting out of sync. Single source of truth preferred.

agreed, this was an initial dump of the internal docs, I'll trim and link where there's duplication but parts of what is in this change aren't easy to find in other places

[skliper]

agreed, this was an initial dump of the internal docs, I'll trim and link where there's duplication but parts of what is in this change aren't easy to find in other places

Understood, which is why I think the README is helpful as a reference to all that "internal" documentation. Much of it is in various sample_defs or cmake implementation files. The closer the documentation is to the implementation the more likely it is kept up to date :)