Aria2c: fix remove and make clear does not support remove data

[bwitt]

For Aria2c:

• fix remove to work on torrents in both active and stopped states
• remove from the list of clients that support remove data (no remove data option in the rpc)

Also for multi select on the torrent list page, only show remove data when the client supports it so that it wont show that option on aria2c.

Fixes #690

[bwitt]

@Tmalll can you check if this fixes your issue? I dont have this setup so I cannot test.