Adding documentation for typical usages of OpenFAST #2290

Job	Run time
build-postlib-release	10m 18s
build-all-debug-single	5m 17s
build-drivers-release	5m 25s
build-all-debug	6m 35s
build-test-uadriver-debug	3m 14s
rtest-module-drivers	2m 40s
rtest-modules-debug	5m 3s
build-interfaces-release	3m 16s
build-openfast-release	2m 58s
build-fastfarm-release	9m 41s
rtest-OF-5MW_OC4Semi_WSt_WavesWN	1m 22s
rtest-OF-5MW_Land_AeroMap	1m 10s
rtest-OF-5MW_Land_BD_DLL_WTurb	1m 59s
rtest-OF	7m 6s
rtest-OF-5MW_OC3Mnpl_DLL_WTurb_WavesIrr	1m 29s
rtest-OF-5MW_OC3Trpd_DLL_WSt_WavesReg	4m 54s
rtest-OF-linearization	2m 45s
rtest-OF-5MW_OC4Jckt_DLL_WTurb_WavesIrr_MGrowth	51s
rtest-OF-simulink	9m 51s
rtest-interfaces	4m 41s
rtest-FF	3m 15s
	1h 33m 50s

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