This commit improves the handling of tabs in the samll deck layout. We
are now saving the selected tabs index in the newly added
"LayoutRepository" so that we can reuse the selected tab when a user
switches between the small and large layout. We can now also set the tab
which should be initially selected in the large layout when a user
selects a column in the navigation rail. Last but not least we can also
reset the initial tab index when a user selects a new deck in the
settings, so that we always display the first column instead of the
column with the same index as it was selected in the previous deck.
The cached items in the "ItemsRepositoryStore" are now cleared when a
user selects an active deck in the settings and when a user signes out
of the app.
This is done to force a reload of the items in a column, when a user
switches between decks. For me this works better because, when I switch
between decks I manually trigger a reload for all columns, which is now
not necessary anymore.
