[rawang] Optimizations for touch layout

[darcywong00]

Follow-on to #1338

User requested the following optimizations for the Rawang touch keyboard

Default layer

• Move punctuation to longpresses on the period key (move to the right of spacebar)
• Keep numerics on top row
• Add long presses to vowels (a, e, i, o, u, ø) and v
• For the long press hint, use the character with high tone
• Next to m, add : key then Backspace
• Changing layers
  • single-tap shift to get to Shift layer
  • double-tap shift to get to Caps lock
  • add key below shift to switch to numeric layer

Shift layer

• Uppercase of default layer, each key returns to default layer

Numeric layer

• Just 3 rows of keys
• top is numerals 1 to 0
• [TBD] next two rows can be copied from sil_euro_latin. User OK that Numeric layer would have an inconsistent number of rows

No need for symbolic layer
No change to desktop rules (even though it has extraneous characters for "s" and "g" keys)

[darcywong00]

PR #2554 has the updated user requests after several rounds of testing...