Allow port to be configurable

Regex:

- `^`        Line start
- `#*\s*`    Find line even if commented out
- `(port)`   'port' -- capture as backreference `\1`
- `\s*=\s*`  Equals sign, whether or not surrounded by whitespace
- `\d{4,5}`  Existing port value, expected at 4/5 digits
- `(.*)`     Remainder (i.e. comment) -- capture as backreference `\2`
- `$`        Line end

pillar.example

@@ -32,6 +32,10 @@ postgres:
     hard: 64000
 
   # POSTGRES
+  # Non-standard port to use for the cluster
+  # Only set if port `5432` is not appropriate
+  port: 5433
+
   # Append the lines under this item to your postgresql.conf file.
   # Pay attention to indent exactly with 4 spaces for all lines.
   postgresconf: |