tmf: Update event properties to use aspects

By using all defined aspects as property descriptors, we can
do away with some of the hard-coded ones, like timestamp and
even type.

Event content could keep its own descriptor though, since it
puts the event fields into a nice sub-tree.

This also makes sure that any extra aspect defined by the
trace type also shows up in the Properties View.

Bug: 460635

Change-Id: Ibea43dd9c6491e660b9732f93419057b6ea721e6
Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>