tmf: Simplify SelectElementTypeContributionItem

tmf: Simplify SelectElementTypeContributionItem

The class TmfTraceType already manages the list of available trace
types, including experiment types and custom trace types. Its list of
trace type helpers can be used to build the menu items.

The unused command parameters BUNDLE and ICON are removed.

Note that menu items will now be grouped by category name instead of
category id. If two different category id used the same name, they will
now be merged instead of showing two sub-menus with the same name.

The items in a category sub-menu will be sorted alphabetically.

Change-Id: I411e88ad34db66d4ec3d32d8e4e6390ca66b6c6a
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/93446
Reviewed-by: Hudson CI
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>