Refactor.
Moved spacers addition up in to constructor just to separate the layout/spacing code and sub-component code somewhat.
Moved heading down in to the panel (rather than in parent container).
BoundingBoxPanel configured to take up two columns - it now looks the same between AodaacPanel and FilterGroupPanel.
Code is a bit more self documenting.
Renamed 'getBL' to somewhat less cryptic 'getBoundingLine'.
Note that the public functions have been kept the same to stay consistent with what GeoNetwork uses.
Merge pull request #659 from aodn/aodaac_wfs_filter_ui_unification

Aodaac wfs filter ui unification