'Jalview Test' installers and applications for www.jalview.org/getdown/test-release/ channel

Currently, installers built with gradle -PCHANNEL=TEST-RELEASE are configured to create installations that have the same application name as a standard RELEASE channel installer.

Instead, when installing an installer for the www.jalview.org/getdown/test-release channel, the installers should provide/install an application with a different name - e.g. "Jalview-Test" (or "Jalview Test" if the platform allows), and the application's default installation path should also be different (e.g. /.../jalview-test/).