Feature/cover crop mode (#225)

Added a setting to select `fit` or `crop` for cover image on sleep
screen.

Might add a `expand` feature in the future that does not crop but rather
fills the blank space with a mirror of the image.

---------

Co-authored-by: Dave Allie <dave@daveallie.com>

src/CrossPointSettings.h

@@ -17,6 +17,7 @@ class CrossPointSettings {
 
   // Should match with SettingsActivity text
   enum SLEEP_SCREEN_MODE { DARK = 0, LIGHT = 1, CUSTOM = 2, COVER = 3, BLANK = 4 };
+  enum SLEEP_SCREEN_COVER_MODE { FIT = 0, CROP = 1 };
 
   // Status bar display type enum
   enum STATUS_BAR_MODE { NONE = 0, NO_PROGRESS = 1, FULL = 2 };
@@ -53,6 +54,8 @@ class CrossPointSettings {
 
   // Sleep screen settings
   uint8_t sleepScreen = DARK;
+  // Sleep screen cover mode settings
+  uint8_t sleepScreenCoverMode = FIT;
   // Status bar settings
   uint8_t statusBar = FULL;
   // Text rendering settings