2021-infrastructure-stable

Due in about 11 months (08/15/2020)

changes to versions of things supported and tested should stabilize at least several weeks before the beta

Related issues
	Task #2916: Decide future of symtab
	Task #2999: Move all logging in core library and tools to use MDLogger
	Task #3013: Extend logging levels in MDLogger
	Task #3015: Create central log handle for calls to gmx_fatal
	Task #3033: Clean up and modernize googletest bundling and usage
	Task #3035: Provide central logger in wrapper binary
	Task #3047: Set required versions for GROMACS 2021
	Task #3072: Use gmx::index for indexing instead of int
	Task #3076: Selectively activate MdModules during simulation instead of instantiating all of them
	Task #3096: Multiple time-stepping: correct coupling algorithms, virial calculation and energy output

GROMACS