Add support for network shares in kio_trash

kio_trash didn't support network shares, causing "trashed" files to be copied into user's home directory.

This patch adds support for them by assigning them persistent ID's (because
there is no device minor/major ID or any other integer we can use) which are
stored in trashrc config file - because we need to share them between
possible multiple kio_trash processes.

Network shares get ID's starting with 6000000 to avoid possible conflicts
with block devices.

NextID is also stored in trashrc file.

BUG: 177023
Change-Id: I5ad180d024fa61f026509435741d9967d97884c2
REVIEW: 125214
FIXED-IN: 5.15