Sort test fixtures and generated tests into folders (#514)
1#[cfg(feature = "grid")]
2mod gridflex_column_integration;
3#[cfg(feature = "grid")]
4mod gridflex_kitchen_sink;
5#[cfg(feature = "grid")]
6mod gridflex_kitchen_sink_minimise;
7#[cfg(feature = "grid")]
8mod gridflex_kitchen_sink_minimise2;
9#[cfg(feature = "grid")]
10mod gridflex_kitchen_sink_minimise3;
11#[cfg(feature = "grid")]
12mod gridflex_row_integration;