KCL: Convert x/y lines to use keyword arguments (#5615)

Previously, `xLine`, `xLineTo`, `yLine` and `yLineTo` used positional arguments. Now:

- `xLineTo` and `yLineTo` have been removed
- `xLine` and `yLine` both use keyword arguments:
  - `length`, optional (i.e. a relative distance along the X or Y axis)
  - `endAbsolute` optional (i.e. an absolute point along the X or Y axis)
  - `tag` optional
- Exactly one of `length` or `endAbsolute` must be given. Not both, not neither.

For example:

```
// Old way
|> xLine(6.04, %)
|> yLineTo(20, %, $base)

// New way
|> xLine(length = 6.04)
|> yLine(endAbsolute = 20, tag = $base)
```

This also improves some of the general-purpose keyword arguments code in modeling app's TS codebase.

e2e/playwright/command-bar-tests.spec.ts

@@ -16,7 +16,7 @@ test.describe('Command bar tests', { tag: ['@skipWin'] }, () => {
   |> startProfileAt([-10, -10], %)
   |> line(end = [20, 0])
   |> line(end = [0, 20])
-  |> xLine(-20, %)
+  |> xLine(length = -20)
   |> close()
     `
       )