Changes

• Add G2Trailing SRS data into SRS struct
  • Discussed with @bxue-l2, since these points are SRS, it makes sense to include them in the struct directly
  • This change enabled the SRS initialization simplifications
• Extract SRS initialization from Prover and Verifier
  • The code in these two locations was nearly identical
  • This abstraction allows me to avoid an additional duplication of this logic, while implementing a further utility which requires SRS