Release 2021.12.15

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From #3612 (Remove function of time names from options):

Remove all FunctionOfTimeName: and InitialExpirationDeltaT: options from input files

Merged pull-requests (15)

General changes (12):

• Add WeylMagnetic (#3215)
• Add Frame::Distorted to Domain (#3677)
• Add TensorIndex n for TensorExpressions (#3680)
• Remove function of time names from options (#3612)
• Apple silicon (#3683)
• Add subcell time derivative to Burgers (#3676)
• Add Burgers subcell executables (#3678)
• Add KH instability analytic data for GRMHD (#3682)
• Update tensor variable names in GeneralRelativity (#3689)
• Mass-conservative restriction in elliptic DG (#3700)
• FindApparentHorizon now stores previous results. (#3692)
• Split NeighborDataForReconstructionAndRdmpTci tag (#3693)

Bugfixes (3):

• Increase tolerance for CCZ4 Ricci tensor and DgSubcell reconstruction unit test cases (#3684)
• Add support for clang-13/Ubunt 21.10 (#3701)
• Set output precision in RunSingleTest (#3695)

Contributors (10): @noora-gn, @gsb76, @macedo22, @knelli2, @geoffrey4444, @yoonso0-0, @nilsdeppe, @nilsleiffischer, @markscheel, @wthrowe