feat: signature rejection (#1472)

## Description

Adds support for rejecting a given document informing the document
owner.

Flows for resolving a rejection don't currently exist so it's up to the
document owner to reach out to the recipient and work out a way to move
forward via a new document or offline agreement.

## Related Issue


## Changes Made

- Added new rejection properties to the recipient schema
- Added API endpoints to support rejection
- Added email templates for notifying the document owner and recipient
- Added a dialog on the signing page to start the rejection flow.

## Testing Performed

- Manually tested the flow end to end
- Automated tests are planned

apps/web/src/app/(signing)/sign/[token]/page.tsx

@@ -99,6 +99,10 @@ export default async function SigningPage({ params: { token } }: SigningPageProp
 
   const { documentMeta } = document;
 
+  if (recipient.signingStatus === SigningStatus.REJECTED) {
+    return redirect(`/sign/${token}/rejected`);
+  }
+
   if (
     document.status === DocumentStatus.COMPLETED ||
     recipient.signingStatus === SigningStatus.SIGNED