Move constants to options prop (#3799)

Another go at #3628 & #3783. This moves (most) constants into
`editor.options`, configurable by the `options` prop on the tldraw
component.

### Change Type

- [x] `sdk` — Changes the tldraw SDK
- [x] `feature` — New feature

### Release Notes

You can now override many options which were previously hard-coded
constants. Pass an `options` prop into the tldraw component to change
the maximum number of pages, grid steps, or other previously hard-coded
values. See `TldrawOptions` for more

packages/editor/src/lib/components/default-components/DefaultHandle.tsx

@@ -1,6 +1,7 @@
 import { TLHandle, TLShapeId } from '@tldraw/tlschema'
 import classNames from 'classnames'
-import { COARSE_HANDLE_RADIUS, HANDLE_RADIUS, SIDES } from '../../constants'
+import { SIDES } from '../../constants'
+import { useEditor } from '../../hooks/useEditor'
 
 /** @public */
 export interface TLHandleProps {
@@ -13,7 +14,8 @@ export interface TLHandleProps {
 
 /** @public */
 export function DefaultHandle({ handle, isCoarse, className, zoom }: TLHandleProps) {
-	const br = (isCoarse ? COARSE_HANDLE_RADIUS : HANDLE_RADIUS) / zoom
+	const editor = useEditor()
+	const br = (isCoarse ? editor.options.coarseHandleRadius : editor.options.handleRadius) / zoom
 
 	if (handle.type === 'clone') {
 		// bouba