tracking #182 (bob de boumaa rework)

[vimwitch]

• [x] move mopro-core logic into mopro-ffi
  • [x] delete mopro-core
  • [x] delete static/const embedded srs/zkey/vkey/etc.
  • [x] accept path to constants when building proofs
• [x] separate UDL interfaces for circom and halo2
  • [x] remove conditional compilation for individual functions (#180)
• [x] clean up examples
  • [x] only store srs/zkey/vkey/wasm files
  • [ ] move the halo2/circom source to a different repo
• [ ] refactor cli
  • [ ] translate build_ios, build_android, build_core into rust (don't simply invoke shell scripts from rust)
  • [x] ios
  • [ ] android
  • [x] delete TOML/mopro-config parsing logic
  • [x] delete shell script cli implementation
  • [x] delete circom build logic (delegate to mopro user)
  • [x] export these functions as functions designed to be used in a build script
• [ ] write an example mobile app project in a separate repo
  • [x] add a build.rs that calls the above rust implementations (build_ios, build_android, etc)
  • [x] build mobile project using cargo build instead of mopro build
  • [x] build lib_mopro_ffi.a from source, specify config in rust source
  • [x] delete toml project config
  • [x] copy zkeys/vkeys/srs/etc to app bundle
  • [ ] only use mopro cli for initializing projects
• [ ] build template from example project

This PR transfers the proving logic from mopro-core to mopro-ffi. The examples directory is removed and the artifacts are committed directly into mopro-ffi/test-vectors. All the circuits except for multiplier2 and keccak256 have been removed.

Proving functions are now:

• generate_circom_proof
• verify_circom_proof
• generate_halo2_proof
• verify_halo2_proof

The halo2/circom logic is also separated so they can be enabled at the same time.

Related #182 Closes #180