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/api/v1/implementation.ts

@@ -233,6 +233,7 @@ export const ApiContractV1Implementation = createNextRoute(ApiContractV1, {
 
       const document = await createDocument({
         title: body.title,
+        externalId: body.externalId || null,
         userId: user.id,
         teamId: team?.id,
         formValues: body.formValues,
@@ -398,6 +399,7 @@ export const ApiContractV1Implementation = createNextRoute(ApiContractV1, {
       teamId: team?.id,
       data: {
         title: fileName,
+        externalId: body.externalId || null,
         formValues: body.formValues,
         documentData: {
           connect: {
@@ -454,6 +456,7 @@ export const ApiContractV1Implementation = createNextRoute(ApiContractV1, {
     try {
       document = await createDocumentFromTemplate({
         templateId,
+        externalId: body.externalId || null,
         userId: user.id,
         teamId: team?.id,
         recipients: body.recipients,