Bug 577564 - add warning dialog before modifying final fields

Added preference and dialog to warn user before modifying final fields
values in debugger either by a context menu or via the embeded value
editor. The new preference is enabled by default.

To disable in a product, following value can be used:
org.eclipse.jdt.debug.ui/org.eclipse.jdt.debug.ui.prompt_before_modifying_final_fields=false

Change-Id: I52a88eb3f1239bf04472f3f5f651be90c2e583b9
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>
Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.debug/+/188471
Tested-by: JDT Bot <jdt-bot@eclipse.org>
6 files changed