[GR-4777] Refactor launcher into separate project using new Engine API.

...fle.r.engine/src/com/oracle/truffle/r/engine/REngine.java

...rc/com/oracle/truffle/r/engine/RRuntimeASTAccessImpl.java

...src/com/oracle/truffle/r/engine/TruffleRLanguageImpl.java

...c/com/oracle/truffle/r/engine/interop/REnvironmentMR.java

...gine/src/com/oracle/truffle/r/engine/interop/RListMR.java

...e/src/com/oracle/truffle/r/engine/interop/RPromiseMR.java

...oracle/truffle/r/engine/shell/EmbeddedConsoleHandler.java

...ngine/src/com/oracle/truffle/r/engine/shell/RCommand.java

...gine/src/com/oracle/truffle/r/engine/shell/REmbedded.java

...oracle/truffle/r/ffi/impl/common/JavaUpCallsRFFIImpl.java

...com/oracle/truffle/r/ffi/impl/nfi/TruffleNFI_PkgInit.java

...her/src/com/oracle/truffle/r/launcher/ConsoleHandler.java

.../com/oracle/truffle/r/launcher/DefaultConsoleHandler.java

.../com/oracle/truffle/r/launcher/JLineConsoleCompleter.java

...rc/com/oracle/truffle/r/launcher/JLineConsoleHandler.java

...uncher/src/com/oracle/truffle/r/launcher/RCmdOptions.java

....launcher/src/com/oracle/truffle/r/launcher/RCommand.java

...e.r.launcher/src/com/oracle/truffle/r/launcher/RMain.java

...ncher/src/com/oracle/truffle/r/launcher/RStartParams.java

...her/src/com/oracle/truffle/r/launcher/RVersionNumber.java