New vibro-acoustic model suite

• New solver: acousticFoam
• New base finite-area region class: regionFaModel
• New base shell model classes:
  • vibrationShellModel
  • thermalShellModel
• New shell models:
  • A vibration-shell model: KirchhoffShell
  • A thermal-shell model: thermalShell
• New finite-area/finite-volume boundary conditions:
  • clampedPlate
  • timeVaryingFixedValue
  • acousticWaveTransmissive
• New base classes for fvOption of finite-area methods: faOption
• New faOptions:
  • contactHeatFluxSource
  • externalFileSource
  • externalHeatFluxSource
  • jouleHeatingSource
• New tutorial: compressible/acousticFoam/obliqueAirJet