Import Improvements - Githubissues

Importing could do with the following improvements:

[x] Show progress / spinner when clicking "import" or all other buttons.
[x] Have the import process (i.e. running the reusable filters) be applied asyncronously, and have the page show the progress.
[x] Consider how the reusable filters could be limited to only specific import types
[x] Make the import list be filterable (and sortable, and shown as a table).
[x] Make the import page show the mapping type that is used (and the import type).
[x] Make the default import be a mapped transaction.

qwacko / totallatorv3