Implement query tool on command line and over SSH

This little query tool is primarily intended for use when running an
embedded H2 database where there really is no other way to access the
in-memory files and state.

It is however handy for quick queries against any other database.

Bug: issue 327
Change-Id: I77a96c0833026d432103a16b48ec36f315c352ec
Signed-off-by: Shawn O. Pearce <sop@google.com>

gerrit-main/src/main/java/com/google/gerrit/main/GerritLauncher.java

@@ -56,6 +56,7 @@ public final class GerritLauncher {
       System.err.println("The most commonly used commands are:");
       System.err.println("  init           Initialize a Gerrit installation");
       System.err.println("  daemon         Run the Gerrit network daemons");
+      System.err.println("  gsql           Run the interactive query console");
       System.err.println("  version        Display the build version number");
       System.err.println();
       System.err.println("  ls             List files available for cat");