Add event logs deletion with filters

[damsfx]

While the event log list allows you to delete events in a bulk fashion by filtering the list with a keyword, then selecting all the events and clicking on the "Delete selected" button, if the log includes more events responding to the query than the list can display, you need to repeat the action several times to delete all the events.

This PR provides a new button to display a pop-up window to the user, allowing him to enter a search term and date range to obtain the set of events matching the criteria, which will be deleted after confirmation.

[LukeTowers]

@damsfx what do you think about instead adding date filters to the list itself and then making a PR to add support for a special "select all" mode that allows you to select all records that match the current query (like gmail has)?

[LukeTowers]

Could even make the select all text even more useful by adding a count to it ("Select all records that match this search (402)")