Summary:
and dropping a collection to define a new favorite.

BUG: 387873

Test Plan:
Tested all three features, reordering, adding, and dropping a mail.

Two issues left:
- adding a new favourite at a specific position (patch pending
      for akonadi's favoritecollectionsmodel)
- the "+" when moving to reorder shouldn't appear, should be MoveAction only,
      don't know if that's possible here though.

Reviewers: dvratil, mlaurent, mkoller

Reviewed By: dvratil

Subscribers: #kde_pim

Tags: #kde_pim

Differential Revision: https://phabricator.kde.org/D9403

Summary:
In order to separate favorites from the "entity order" QSFPM
used by the folder tree widget (it was always weird that filtering or
changing the sort order for the folder tree widget would affect favorites),
we need the favorites to get their own "ordering" proxy (otherwise
ordering is random, based on ETM population order). So while at it,
I implemented manual reordering of favorites.

BUG: 376073
FIXED-IN: 18.04

Test Plan:
I can reorder favorites (in listview mode) using DnD
and the order is persisted

Reviewers: dvratil, mlaurent

Reviewed By: mlaurent

Subscribers: #kde_pim

Tags: #kde_pim

Differential Revision: https://phabricator.kde.org/D8884

Summary:
This way the FolderTreeWidgetProxyModel (its source) doesn't get
filtered, which will allow FavoriteCollectionsModel to not get filtered
by the filter lineedit (once it uses FolderTreeWidgetProxyModel
directly).

This also simplifies FolderTreeWidgetProxyModel.

Test Plan: lineedit filtering in kmail still works

Reviewers: dvratil, mlaurent

Reviewed By: mlaurent

Subscribers: #kde_pim

Tags: #kde_pim

Differential Revision: https://phabricator.kde.org/D8818

The old text said "will be uploaded" which is wrong,
the new text is also more positive but still communicates
the problem.

There was a warning for the encrypt action but not for the
decrypt action. It should be warned that end-to-end encryption
no longer exists if the decrypted mails are stored in a
remote resource.

Differential Revision: https://phabricator.kde.org/D8679

This fixes filtering on non-IMAP resources as the current implementation
only considers for filtering folders with server-side name "INBOX" or
the default Inbox collection for the Akonadi instance. If the resource
uses a different server-side identifier for its Inbox folder it will not
get filtered.

The updated implementation will consider all Inbox-type folders for all
resources that have registered such folders.

Reviewers: #kde_pim, dvratil

Reviewed By: #kde_pim, dvratil

Tags: #kde_pim

Differential Revision: https://phabricator.kde.org/D3181