In case a widget uses its own scrollareas for dynamic resizing
(for example the store), setting `implements_scrollarea` to `True`
will avoid the encapsulating scrollarea of the container.
Introduces the LibraryLayout from #196.
This layout distributes the available space in either horizontal side and in-between the widgets.
Known issues: When searching for a game, it will re-align visible widgets, effectively centering the results.
This is because the search and grouping functions are interleaved. #196 handles it differently by adjusting
the opacity and re-ordering of the irrelevant widgets.
Signed-off-by: loathingKernel <142770+loathingKernel@users.noreply.github.com>
