* Add FutureUtilTest for both FutureUtil.batchAndParallelExecute and FutureUtil.batchAndSyncExecute
* Make Vector same size as available processors as CI machines don't have as many processors as I have locally
* Try to fix test case
* Add processors to the log
* Replace java scheduler with a scalajs scheduler called monix
* Make asyncUtilsTest compatible with Scalajs, add them to the CI matrix
* Add more missing runs of asyncUtilsTestJS/test
* Fix missing database shutdown on WalletAppConfig.stop()
* Cleanup BitcoindBlockPollingTest
* Cleanup ProcessBlockTest and all tests that use CachedBitcoind
* Cleanup BitcoindBackendTest
* Cache rescan thread pool rather than creating a new one everytime
* Refactor AsyncUtil to just use an execution context rather than an actor system
* Create async util project, use it in various projects that depend on it
