Make updates for colour scheme

(cherry picked from commit 9388ee6cee2d0db4de407cc4fe4264e90cc37f02)
Rename updateColourScheme for ease of debugging

(cherry picked from commit 242e738fe495028be362f52c4d4f5332a804bb2a)
Ensure colour scheme combo gets updated when activate is called

(cherry picked from commit 19cfd8a94c9bdc183f48b24c7aa04db1ec556312)
Defensively call deactivate and ensure paletteData is null to avoid caching issues

(cherry picked from commit bbf70a4b4fef1d58fe4f376be2712ec6c1f95019)
Set palettedata without using cached value to avoid bugs with dedicated view

(cherry picked from commit fa339a54640484c8df44600d224d9613196639b3)
Ensure RGB combos get updated correctly

(cherry picked from commit 1a26f6040944682ce16074beb5d442cd98bd1173)
Fix bug to make histo-range and b&c update when roi changes

(cherry picked from commit a4b9e29df0768794cff660bae7d2b44f20a722ef)
Ensure updates happen for brightness, contrast and histogram range ux

(cherry picked from commit ff86a8974c3e87e63a96a93ecc6fdd9967f38da2)
Code clean up & commenting

(cherry picked from commit 8d03a27c0f23b4de57a514829a6145c79e3d2e93)
Change order of events as workaround for lack of notification for pallette name changing.

(cherry picked from commit fdf1efca9d0672f001a48cb184b33b50898e0ebf)
Merge branch 'gda-8.42_colour_mapping_usability_branch' into gda-8.42