fix: change the default server port (#145)

Description

• change the default value of server port: 3001 to 2400
• take into account the documentation (docs!69 (merged))

Related issue

#145 (closed)

Examples

app:
  # HTTP server port. By default: 2400.
  port: 2400

Checklist

• the MR description has been reviewed
• this MR contains text changes and they have been reviewed OR there are no texts changes
• this MR contains GUI/CLI changes and they have been reviewed OR there are no GUI/CLI changes
• this MR contains API changes and they have been reviewed OR there are no API changes

Closes #145 (closed)