Split out MerkleTree contract and emit CapeBlock as part of BlockComm…

…itted event (#1097)

* Emit CapeBlock as part of BlockCommitted event

* Run cargo update

* Emit block data fields individually

If we emit the CapeBlock struct directly this leads to a compilation
error. The workaround to emit ABI encoded bytes instead fails to decode
the CapeBlock in rust struct at runtime. This workaround emits the
ABI encoded fields of CapeBlock individually.

The function `decode_cape_block` uses an ugly workaround to deal with
the problem of not being able to import `BlockCommittedFilter` because
that type exists both for `CAPE` and `TestCAPE` and is therefore
ambiguous.

* cargo update to get latest ethers-rs version

* Remove ambigous type workaround

* Organize imports

* [WIP] Separate merkle tree contract

- Create ownable merkle tree contract owned by CAPE.

* undo unwanted changes

* Add missing file

* All tests pass.

- Add missing public getters.
- Remove tree height constructor arg from CAPE.

* Update hardcoded contract addresses

* Check access control of merkle tree contract

After running `hardhat deploy` check that

1. The merkle tree contract is owned by the CAPE contract.
2. The deployer can no longer add elements to the merkle tree.

* Fix typescript tests

* Fix typo

* Use 1000 solc optimizer runs instead of 20

Using a really high (e.g. 1M) number does have a significant
impact on gas usage but also leads to a contract that is too
big to deploy. With 1000 runs the CAPE contract is as 22.5 kB
so there is still room to make changes to the contract.

* Build executables before exporting wallet docs

* More consistency

* Remove the geth patch that enables >24kB contracts

* Revert "Remove the geth patch that enables >24kB contracts"

This reverts commit b716ae2.

Re-enable failing compilation if CAPE code is > 24kB

The TestCAPE contract is still too big unless we use a very low number
of optimizer runs.

* Update smart contract architecture diagram

.github/workflows/build.yml

@@ -33,7 +33,7 @@ jobs:
       - uses: cachix/cachix-action@v10
         with:
           name: espresso-systems-private
-          authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
+          authToken: "${{ secrets.CACHIX_AUTH_TOKEN }}"
 
       - uses: actions/checkout@v2
         name: Checkout Repository
@@ -68,6 +68,9 @@ jobs:
       - name: Generate Docs
         run: nix-shell --run "prepend-timestamps make-doc"
 
+      - name: Build all executables
+        run: nix-shell --run "cargo build --release"
+
       - name: Generate Wallet
         run: ./target/release/export-wallet-api-docs --api ./wallet/api/api.toml --assets ./wallet/public/ ./doc/mdbook/book/wallet
 
@@ -79,9 +82,6 @@ jobs:
           publish_dir: ./doc/mdbook/book/
           cname: cape.docs.espressosys.com
 
-      - name: Build all executables
-        run: nix-shell --run "cargo build --release"
-
       - name: Build demo geth data dir
         run: nix-shell --run "demo/initialize-demo-geth"