[Feature Request] Implement -Qs for apt

[AndydeCleyre]

Hello, and thanks!

I expect this is already planned, but I didn't see a tracking issue, just the current compatibility table confirming that installed packages can't yet be searched (qs in the table), using apt.

[rami3l]

@AndydeCleyre Many thanks for the ping!

-Qs does seem to be a forgotten command in pacaptr's migration to apt since there's still no direct equivalent of it there. (apt list is still "in the works" and it seems impossible currently to use it for description searches.)

However, I should be able to make an addition real quick using dpkg -l. Stay tuned!