Add CLA and CLA workflow

[ronald-jaepel]

Other steps taken (Formulation taken from Michael Ostheges summary)

• Created https://github.com/cadet/cla-signatures (private) for storing CLA signatures

• Created a fine-grained personal access token to be used by the GH Action for writing the signatures into the private repo

  • Under https://github.com/settings/personal-access-tokens/new
  • Token name CADET_CLA_SIGNATURES
  • Expiration 2025-06-23 (maximum is 1 year)
  • Resource owner cadet👈 This filters which repositories are available in the dropdown below!
  • Select repository: cadet/CLA-signatures
  • Permissions on Content must be set to Read & Write.
  • Added it as a secret CADET_CLA_SIGNATURES in the modsim/cadet project