feat: add docker support and docker-compose quickstart

Add support for production container builds using the provided `Dockerfile` and `build.sh` script. This can later be used with actions to automatically publish to the provided docker registry.

Additionally, support an accelerated developer quickstart using `docker-compose`. Developers can now run the `dx` npm command to quickly spin up a database and mail server.

.env.example

@@ -1,6 +1,9 @@
 # Database
 # Option 1: You can use the provided remote test database, courtesy of the documenso team: postgres://documenso_test_user:GnmLG14u12sd9zHsd4vVWwP40WneFJMo@dpg-cf2hljh4reb5o45oqpq0-a.oregon-postgres.render.com/documenso_test_e2i3
 # Option 2: Set up a local Postgres SQL instance (RECOMMENDED)
+# Option 3: Use the provided dx setup (RECOMMENDED)
+#   => postgres://documenso:password@127.0.0.1:5432/documenso
+#
 # ⚠ WARNING: The test database can be resetted or taken offline at any point.
 # ⚠ WARNING: Please be aware that nothing written to the test databae is private.
 DATABASE_URL=''
@@ -20,6 +23,12 @@ SENDGRID_API_KEY=''
 
 # SMTP
 # Set SMTP credentials to use SMTP instead of the Sendgrid API.
+# If you're using the dx setup you can use the following values:
+#
+# SMTP_MAIL_HOST='127.0.0.1'
+# SMTP_MAIL_PORT='2500'
+# SMTP_MAIL_USER='documenso'
+# SMTP_MAIL_PASSWORD='documenso'
 SMTP_MAIL_HOST=''
 SMTP_MAIL_PORT=''
 SMTP_MAIL_USER=''
@@ -30,4 +39,4 @@ MAIL_FROM='documenso@localhost.com'
 
 #FEATURE FLAGS
 # Allow users to register via the /signup page. Otherwise they will be redirect to the home page.
-ALLOW_SIGNUP=true
+ALLOW_SIGNUP=true