landscapeapp Add options to change the main page design

Relates to Issue #834

For items with the large_item flag, this PR adds configurable options to change the label text and label colour. It also provides an alternative_layout option which offers a different design scheme for categories on the main page.

The new completely optional config options here are big_picture_label_color, big_picture_label_type (ie whether the label is the project or item name), display_name (this allows a different display name to be set when the label type is item name) and alternative_layout. The display name also would show instead of the item name at the top of the item's dialog box. All of these configs are completely optional.

big_picture_label_color simply sets the colour of the large item label. big_picture_label_type relates to what the label text actually shows - if set to Item or item the label shows the item name rather than the item project (in the future more values other than item can be added to make the text something different). big_picture_label_color and big_picture_label_type would go in settings.yml, in relation -> values, like so:

# settings.yml
relation:
  values:
    big_picture_label_color: black
    big_picture_label_type: Item

display_name would go in landscape.yml below the name for an item, like so:

# landscape.yml
landscape:
  - category:
    subcategories:
      - subcategory:
        name: ...
        items:
          - item:
            name: ...
            display_name: ...

So if the landscape without any of the new configs set looks like this: Screenshot from 2022-07-26 14-13-46

When alternative_layout is set to true and big_picture_label_color and big_picture_label_type are set, the above landscape can change to look like this: Screenshot from 2022-07-26 14-13-06 Notice that the labels for the large items are larger and can be adjusted to show the item name instead of the project name, or any custom text and color.