feat: allow keyboard to output Ctrl character combinations

**Is your feature request related to a problem? Please describe.**
Currently there is no way with Keyman to output a changed Ctrl key. For example, a French keyboard swaps the A and Q keys, but using
```
+ [CTRL K_A] > [CTRL K_Q]
```
gives an error.

Use case: From keyboards repo: release/e/engram
The keyboard rearranges keys for more efficient typing (similar to the motivation behind the Dvorak keyboard), and author expected Ctrl keys to be rearranged as well.

Use case: I do know that I've been bit when using a Microsoft French keyboard with Z and W switched: I tried to "undo" with Ctrl+Z, but actually got a Ctrl+W and closed the tab. I can imagine that a Keyman keyboard based on a French layout, where the Ctrl keys still follow US-English (the way it is currently), could be confusing for someone used to typing with Ctrl on a QWERTY keyboard.

MD: It should be possible but there's a bunch of interactions that would need to be thought through.

**Describe the solution you'd like**
Allow [CTRL K_??] on the right hand side of a rule.

**Describe alternatives you've considered**
Do nothing and let the Ctrl characters follow the US English layout.

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