FCRM-5399 - Map colours are now set client-side as per the prototype (#…

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* FCRM-5399 set default zoom to england

* FCRM-5399 fixed feature layer (no DEV suffix)

* FCRM-5399 changes to make map full screen

* FCRM-5399 added main rivers, updated feature layer colours to match prototype

* FCRM-5399 moved some repeated itemDefinitions to a keyed object

* FCRM-5399 custom colours show, but only after a timeout

* FCRM-5399 removed commented out style section

* FCRM-5399 added a commented section that will show the style layers names in case they change