Add Solidity linter (#608)

* Add solhint and basic configuration

* Add solhint-plugin-prettier to run prettier via solhint

* Remove all solhint-disable rules in contracts

* Turn off compiler version errors

* Fix max-line-length linter errors

* Fix linting and prettier issues in contracts

* Add global lint command to run both ts and solidity linter

docs/architecture/features.rst

@@ -42,8 +42,6 @@ The only requirement is that the Feature implements the interface in `IFeature <
     /// @dev Basic interface for a feature contract.
     interface IFeature {
 
-        // solhint-disable func-name-mixedcase
-
         /// @dev The name of this feature set.
         function FEATURE_NAME() external view returns (string memory name);
 
@@ -70,7 +68,7 @@ We use this checklist to review the safety of new Features.
     - [ ] No direct access to another feature’s storage bucket without strong justification.
     - [ ] No executing arbitrary calldata from the context of the Exchange Proxy.
     - [ ] No external calls to arbitrary contracts from within the Exchange Proxy.
-    - [ ] Features use unique StorageIds. 
+    - [ ] Features use unique StorageIds.
     - [ ] Document functions with execution contexts outside of the Exchange Proxy.
     - [ ] Document feature dependencies in checklist doc.
     - [ ] Document reentrant functions in checklist doc.