test(rpc): Add Rust tests for lightwalletd sync from Zebra (#4177)

* Make the lightwalletd integration test take a test type

* Configure lightwalletd tests based on the test type

* Remove obsolete kill_on_error() in the lightwalletd test

* Refactor to simplify the test function

* Move LightwalletdTestType to the lightwalletd module

* Create a test function that runs the full lightwalletd test suite

* Actually use the cached Zebra state

* Add checks for the new integration test modes

* Populate the lightwalletd state dir in the FullSyncFromGenesis test

* Fix up state handling, fail earlier if state is invalid

* Adjust timeouts and regex escapes

* Make state requirements for each test stricter

* Move configs to the top of the test function

* Allow unexpected lightwalletd cached state in some tests

* Speed up tests slightly by removing an intermittent log check

* Move timeout selection into test type methods

* Move failure messages into test type methods

* Turn a function argument into an enum field

* Check lightwalletd state directly, rather than Zebra RPC results

* Update gRPC tests for function argument changes

* Remove duplicate env var constant and redundant code