Allow use of custom logo with the JOC Cockpit start window

Feature

• The JOC Cockpit GUI allows to add a custom logo to the start screen.
  • This is helpful to immediately identify if a JOC Cockpit instance is used for production or non-production environments.
• The custom logo position can be located with the top or with the bottom of the screen.
• The following types of logo files are supported:
  • apng
  • .gif
  • .jpg, .jpeg, .jfif, .pjpeg, .pjp
  • .png
  • .svg
• A custom logo is stored to the following location:
  • On premises: JETTY_BASE/webapps/root/ext/images
  • Container: JETTY_BASE/resources/joc/image