Change ESSL colorisation approach

Change the approach for ESSL colorisation.  Remove the dedicated class
and instead define a colourmap to be used with the colorize enhancement.
Fix the ratio to be the right way around.

Fixes and closes 3020.

satpy/etc/composites/visir.yaml

@@ -626,8 +626,8 @@ composites:
       is still under development and may be subject to change.
     compositor: !!python/name:satpy.composites.RatioCompositor
     prerequisites:
-    - wavelength: 0.86
     - wavelength: 0.905
+    - wavelength: 0.86
     standard_name: essl_colorized_low_level_moisture
 
   day_essl_colorized_low_level_moisture:
@@ -638,7 +638,7 @@ composites:
     day_night: day_only
     prerequisites:
     - name: essl_colorized_low_level_moisture
-    standard_name: day_essl_colorized_low_level_moisture
+    standard_name: image_ready
 
   rocket_plume_day:
     description: >

satpy/etc/enhancements/generic.yaml

@@ -1243,12 +1243,114 @@ enhancements:
   essl_colorized_low_level_moisture:
     name: essl_colorized_low_level_moisture
     operations:
-      - name: essl_moisture
-        method: !!python/name:satpy.enhancements.atmosphere.essl_moisture
-
-  day_essl_colorized_low_level_moisture:
-    standard_name: day_essl_colorized_low_level_moisture
-    operations: []
+      - name: colorize
+        method: !!python/name:satpy.enhancements.colorize
+        kwargs:
+          palettes:
+          - min_value: 0.625
+            max_value: 0.91
+            values:
+              - 0.6250
+              - 0.6290
+              - 0.6331
+              - 0.6372
+              - 0.6414
+              - 0.6456
+              - 0.6499
+              - 0.6542
+              - 0.6586
+              - 0.6631
+              - 0.6676
+              - 0.6722
+              - 0.6768
+              - 0.6815
+              - 0.6863
+              - 0.6911
+              - 0.6960
+              - 0.7010
+              - 0.7061
+              - 0.7112
+              - 0.7164
+              - 0.7216
+              - 0.7270
+              - 0.7324
+              - 0.7380
+              - 0.7436
+              - 0.7492
+              - 0.7550
+              - 0.7609
+              - 0.7668
+              - 0.7729
+              - 0.7790
+              - 0.7853
+              - 0.7916
+              - 0.7980
+              - 0.8046
+              - 0.8113
+              - 0.8180
+              - 0.8249
+              - 0.8319
+              - 0.8390
+              - 0.8463
+              - 0.8537
+              - 0.8612
+              - 0.8688
+              - 0.8766
+              - 0.8845
+              - 0.8925
+              - 0.9007
+              - 0.9091
+            colors:
+              - [63, 0, 47]
+              - [58, 0, 50]
+              - [53, 0, 52]
+              - [48, 0, 54]
+              - [42, 0, 56]
+              - [37, 0, 58]
+              - [32, 0, 59]
+              - [27, 5, 60]
+              - [22, 11, 61]
+              - [16, 17, 62]
+              - [11, 23, 63]
+              - [6, 28, 63]
+              - [1, 34, 63]
+              - [0, 40, 63]
+              - [0, 46, 63]
+              - [0, 52, 62]
+              - [0, 58, 62]
+              - [0, 64, 61]
+              - [0, 70, 60]
+              - [0, 76, 58]
+              - [0, 82, 57]
+              - [0, 88, 55]
+              - [0, 94, 53]
+              - [0, 100, 51]
+              - [3, 106, 49]
+              - [17, 112, 46]
+              - [31, 118, 43]
+              - [44, 124, 40]
+              - [58, 130, 37]
+              - [72, 136, 35]
+              - [86, 141, 42]
+              - [100, 147, 50]
+              - [114, 153, 58]
+              - [128, 159, 66]
+              - [142, 165, 74]
+              - [156, 171, 81]
+              - [169, 177, 89]
+              - [183, 183, 97]
+              - [197, 189, 105]
+              - [211, 195, 113]
+              - [225, 201, 120]
+              - [239, 207, 128]
+              - [253, 213, 136]
+              - [255, 219, 144]
+              - [255, 225, 152]
+              - [255, 231, 160]
+              - [255, 237, 167]
+              - [255, 243, 175]
+              - [255, 249, 183]
+              - [255, 255, 191]
 
   rocket_plume:
     standard_name: rocket_plume