Equilibrium metrics patches

[kpentland]

Updates:

1. Patching issue Triangularity calculations #38.
2. Patching definitions of poloidal beta, toroidal beta, and internal inductance to match those in other codes (i.e. Fiesta, EFIT++, and Topeol). We now have:

• poloidalBeta1 to poloidalBeta4 definitions.
• toroidalBeta1 to toroidalBeta4 definitions.
• internalInductance1 to internalInductance5 (internalInductance1 and 2 are new, 4 and 5 are the previous 1 and 2).
  These have been verified to match values from the other codes in MAST-U plasmas (offline).

[nicamo]

thanks @kpentland