Migrate Remaining FAST Documentation and Tests into OpenFAST

[jjonkman]

All former FAST module-level documentation should now be included in OpenFAST's documentation i.e. migrated into ReadTheDocs. Likewise, all former module-level CertTest should now be included in OpenFAST's r-test. The most time-critical items have been identified in separate issues (#176, #177, #178, #179, and #180). The remaining documentation and tests should be included to complete the migration from FAST to OpenFAST. These include:

• ElastoDyn and ServoDyn documentation from the former FAST v7 User's Guide (https://nwtc.nrel.gov/system/files/FAST.pdf).
• InflowWind documentation (https://wind.nrel.gov/nwtc/docs/InflowWind_Manual.pdf) and CertTest.
• TMD documentation (https://nwtc.nrel.gov/system/files/TMD_theory_manual.pdf) and tests.
• SubDyn documentation (https://wind.nrel.gov/nwtc/docs/SubDyn_Manual.pdf) and CertTest.
• OrcaFlex Interface documentation and tests.
• NWTC Subroutine Library documentation (http://wind.nrel.gov/nwtc/doxygen/nwtc_library/html/index.html).
• NWTC Programmer's Handbook (https://nwtc.nrel.gov/system/files/ProgrammingHandbook_Mod20130717.pdf).

[andrew-platt]

Let's require the SubDyn documentation and CertTests item on this list as part of the TCF pull request (whenever that gets issued).

[andrew-platt]

It would be really useful to add diagrams of the various coordinate frames to documentation on readthedocs. For example, how the nacelle (xn etc), yaw-bearing/base-plate (xp etc), tower (xt etc) coordinate systems relate to each other is not always obvious to the users. Most of this information exists in the FAST 6 users guide (and other newer guides), but that is not readily available to most users.

[andrew-platt]

• Add the ExtPtfm documentation: https://github.com/OpenFAST/openfast/files/3698656/ExtPtfm-DevelopmentPlan.pdf (or .rst format version of relevant pieces)

[andrew-platt]

• add documentation on linearization and mode shape visualization to readthedocs

[andrew-platt]

• add documentation on linearization and mode shape visualization to readthedocs
• add documentation on HydroDyn state-space excitation, and how to generate the *.ssextn input files

[Echolon]

Hi @andrew-platt
one short organizational suggestion: Add all added task into the first comment, only then those will be recognized by Github!