CCPP Tech Doc Updates for UFS SRW v2.2 release

[ligiabernardet]

Please edit/add as needed

• [x] Information on the various (and preferred) ways to add connect a scheme to CCPP, including pros/cons of using a wrapper versus pre- and post- interstitials
• [x] Best practices and guidelines wrt ways to allocate memory so schemes can be stateless (recommended but not required) (@dustinswales pls add as needed)
• • [x] Suggest not using the term stateless because audience may not know what it is
• • [x] Schemes should not use dynamic memory allocation on the HEAP
• • [x] Schemes should not contain data that clashes when multiple non-interacting instances of the scheme are being used in one executable"
• • [x] No allocations in module memory
• [ ] More detailed code contribution instructions
• [x] Add note about problem fixed in https://github.com/ufs-community/ccpp-physics/pull/106
• [x] "Single Column Model" --> "Single-Column Model"

[mkavulich]

Preliminary draft of chapter on adding a new scheme to CCPP here: https://docs.google.com/document/d/1DSRt_okwgc1MM6PRiy551RTV4rDXPqpUbKsy4dppf2Y/edit

[mkavulich]

All items but one were complete; the incomplete one has been rolled into #70