keyboards: add wide Belgian layout

This is a copy of the `be` layout with modified key dimensions to fit a 
wide arrangement.

data/keyboards/be_wide.yaml

@@ -0,0 +1,89 @@
+---
+outlines:
+    default:   { width: 54,  height: 42 }
+    altline:   { width: 81,  height: 42 }
+    wide:      { width: 100, height: 42 }
+    spaceline: { width: 205, height: 42 }
+    special:   { width: 54,  height: 42 }
+
+views:
+    base:
+        - "a z e r t y u i o p"
+        - "q s d f g h j k l m"
+        - "Shift_L   w x c v b n .   BackSpace"
+        - "show_numbers preferences         space        show_eschars Return"
+    upper:
+        - "A Z E R T Y U I O P"
+        - "Q S D F G H J K L M"
+        - "Shift_L   W X C V B N ,  BackSpace"
+        - "show_numbers preferences         space        show_eschars Return"
+    numbers:
+        - "1 2 3 4 5 6 7 8 9 0"
+        - "@ # € % & - _ + ( )"
+        - "show_symbols   , \" ' colon ; ! ?  BackSpace"
+        - "show_letters preferences         space        show_eschars Return"
+    symbols:
+        - "~ ` | · √ π τ ÷ × ¶"
+        - "© ® £ $ ¥ ^ ° * { }"
+        - "show_numbers_from_symbols   \\ / < > = [ ]  BackSpace"
+        - "show_letters preferences         space        show_eschars Return"
+    eschars:
+        - "à â ç é è ê î ô ù û"
+        - "À Â Ç É È Ê Î Ô Ù Û"
+        - "show_numbers_from_symbols  æ œ ä ë ï ö ü  BackSpace"
+        - "show_letters preferences         space        show_eschars Return"
+
+buttons:
+    Shift_L:
+        action:
+            locking:
+                lock_view: "upper"
+                unlock_view: "base"
+        outline: "altline"
+        icon: "key-shift"
+    BackSpace:
+        outline: "altline"
+        icon: "edit-clear-symbolic"
+        action: erase
+    preferences:
+        action: "show_prefs"
+        outline: "special"
+        icon: "keyboard-mode-symbolic"
+    show_numbers:
+        action:
+            set_view: "numbers"
+        outline: "wide"
+        label: "123"
+    show_numbers_from_symbols:
+        action:
+            set_view: "numbers"
+        outline: "altline"
+        label: "123"
+    show_letters:
+        action:
+            set_view: "base"
+        outline: "wide"
+        label: "abc"
+    show_symbols:
+        action:
+            set_view: "symbols"
+        outline: "altline"
+        label: "*/="
+    show_eschars:
+        action:
+            locking:
+                lock_view: "eschars"
+                unlock_view: "base"
+        outline: "altline"
+        label: "âÂ"
+    space:
+        outline: "spaceline"
+        text: " "
+    Return:
+        outline: "wide"
+        icon: "key-enter"
+        keysym: "Return"
+    colon:
+        text: ":"
+    "\"":
+        keysym: "quotedbl"