Aiken branch: not using hardcoded files

[NicolasDP]

Currently, we use hardcoded files for our example and execution:

• plutus-halo2-verifier-gen/src/plutus_gen/mod.rs

  Lines 40 to 51 in dd9d0e2

  	let verifier_template_file = match S::kzg_type() {
  	KzgType::GWC19 => Path::new("plutus-verifier/templates/verification_gwc19_kzg.hbs"),
  	KzgType::Halo2MultiOpen => {
  	Path::new("plutus-verifier/templates/verification_halo2_kzg.hbs")
  	}
  	};
  	let vk_template_file = Path::new("plutus-verifier/templates/vk_constants.hbs");
  	let verifier_generated_file =
  	Path::new("plutus-verifier/plutus-halo2/src/Plutus/Crypto/Halo2/Generic/Verifier.hs");
  	let vk_generated_file =
  	Path::new("plutus-verifier/plutus-halo2/src/Plutus/Crypto/Halo2/Generic/VKConstants.hs");

• plutus-halo2-verifier-gen/src/plutus_gen/mod.rs

  Lines 86 to 97 in dd9d0e2

  	emit_verifier_code_aiken(
  	Path::new("aiken-verifier/templates/verification.hbs"),
  	Path::new("aiken-verifier/aiken_halo2/lib/proof_verifier.ak"),
  	&circuit_representation,
  	)
  	.map_err(|e| e.to_string())?;
  	emit_vk_code_aiken(
  	Path::new("aiken-verifier/templates/vk_constants.hbs"),
  	Path::new("aiken-verifier/aiken_halo2/lib/verifier_key.ak"),
  	&circuit_representation,
  	)
  	.map_err(|e| e.to_string())?;

This makes it hard to run different examples and to compare results as we need to save files/rename etc. and retry. Allowing the execution of these high-level routines to be configured would help with being able to generate execution routines to guard/test the CI or even for developers or users to define how the execution of their programme should look like.