[WIP] tmf: Remove filter IDs, use event aspects instead

This reworks the Filter View and Event table to store/use
event aspects, instead of custom filter ID strings.

This allows filtering on any aspect without having to define
a specific Filter ID beforehand (should then work with user-
defined aspects).

Change-Id: If28441152645fbe8fd7bff7f27b1b84053b16925
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>