[Feature] `testnet2` checklist

[howardwu]

trafficstars

🚀 Feature

testnet2 todos are as follows:

Core changes:

• [x] #228
  • [x] #241
  • [x] #251
• [x] #264
• [x] #271

Ledger changes:

• [x] #272
• [ ] #273
• [ ] #280
• [x] #305
• [x] #307

Transaction changes:

• [x] #229
  • [x] #258
• [x] #270
• [x] #304
• [ ] Add Marlin universal parameters, and update the integration test to reflect it
• [x] Fix the Marlin inputs for constraints (@weikengchen)
• [x] Offline/Online update for signing
• [x] Remove program commitments from final transaction struct
• [ ] Bake in network ID enforcement in inner circuit
• [x] Increase memo size to 64 bytes

Record changes:

• [x] #306
• [x] Increase the payload size to 128 bytes
  • [x] #288
• [x] Remove serial number nonce randomness
  • [x] #297

[howardwu]

#241