feat: add email domains (#1895)

Implemented Email Domains which allows Platform/Enterprise customers to
send emails to recipients using their custom emails.

.env.example

@@ -105,6 +105,12 @@ NEXT_PRIVATE_MAILCHANNELS_DKIM_PRIVATE_KEY=
 # OPTIONAL: Displays the maximum document upload limit to the user in MBs
 NEXT_PUBLIC_DOCUMENT_SIZE_UPLOAD_LIMIT=5
 
+# [[EE ONLY]]
+# OPTIONAL: The AWS SES API KEY to verify email domains with.
+NEXT_PRIVATE_SES_ACCESS_KEY_ID=
+NEXT_PRIVATE_SES_SECRET_ACCESS_KEY=
+NEXT_PRIVATE_SES_REGION=
+
 # [[STRIPE]]
 NEXT_PRIVATE_STRIPE_API_KEY=
 NEXT_PRIVATE_STRIPE_WEBHOOK_SECRET=