feat: add external id to documents and templates (#1227)

## Description

Adds the external ID column to documents and templates with an option to
configure it in the API or UI.

External ID's can be used to link a document or template to an external
system and identify them via webhooks, etc.

packages/trpc/server/document-router/schema.ts

@@ -55,6 +55,7 @@ export const ZSetSettingsForDocumentMutationSchema = z.object({
   teamId: z.number().min(1).optional(),
   data: z.object({
     title: z.string().min(1).optional(),
+    externalId: z.string().nullish(),
     globalAccessAuth: ZDocumentAccessAuthTypesSchema.nullable().optional(),
     globalActionAuth: ZDocumentActionAuthTypesSchema.nullable().optional(),
   }),