reader: remove JavaScript client
reader: remove JavaScript client

Remove the JavaScript client for the Reader app, and also modify
vanadium-reader-test so that it runs the Gradle java test instead of
Makefile.

Change-Id: I655007115da5b8f8d3ad944214074eea32cdab36
MultiPart: 2/2

vanadium/go.devtools,vanadium/go.devtools,vanadium/go.devtools