Import history

[sohrab-]

Maintain a history of previously imported transactions.

In the import sidebar, when new queries are run, if there are previous transaction previews, they should be pushed down but still visible for importing.

• Maintain say 10 previous previews
  • Can be configurable in the options, but set an upper limit so the tab memory doesn't get out of hand
• Clear All button
• Should be timestamped
• Should be collapsable - both as a whole and individually?