Remove obsolete variables and their left over functionality

[chris-ashe]

There are some variables which seem to be obsolete though are still hanging around in the code. They should be removed

• fimpvar seems to be obsolete though is not stated as such

• impvar id obsolete so should be documented as such

• ifispact and all associated variables should be removed, as it is not used.

• rho_ecrh seems to be obsolete so should be removed.

• All fms* variables seem to be useless
  real(dp) :: fmsbc
  !! Martensitic fraction of steel in (non-existent!) bucking cylinder

  real(dp) :: fmsbl
  !! Martensitic fraction of steel in blanket

  real(dp) :: fmsdwe
  !! Martensitic fraction of steel in cryostat

  real(dp) :: fmsdwi
  !! Martensitic fraction of steel in vacuum vessel

  real(dp) :: fmsfw
  !! Martensitic fraction of steel in first wall

  real(dp) :: fmsoh
  !! Martensitic fraction of steel in central solenoid

  real(dp) :: fmssh
  !! Martensitic fraction of steel in shield

  real(dp) :: fmstf
  !! Martensitic fraction of steel in TF coil

• farc4tf seems to be obsolete and should be removed

• quench_detection_ef seems to be obsolete. CHECK QUENCH MODEL

• iprimnloss seems to be obsolete

• divleg_profile_inner and divleg_profile_outer seem to be obsolete

• fgamp is seemingly obsolete