QOL improvement requests

[Eseem91]

1: Please make "View All" the default view, there's only two days of the year where the current "show nothing until filters are selected" logic makes sense: CTP.

2: Please delete all cleared clearances after a timeout from entry. Currently online with more than 40 irrelevant clearances.

3: On the same note, please make it easier to delete multiple clearances.

4: Search engine: It is not working at all for me when searching for partial or full callsigns, with or without wildcard (*). Firefox.

5: Optional notification sound for new pending messages.