Row format placeholder prefix - add user control

[miroslavpojer]

Background

In the current implementation, the user cannot control the content of the placeholder prefixes.
Example: {developer-by}

Feature

Add logic to control the prefix bu user:
Examples:

• {developer-by} ==> add the list of developers' logins
• {by|developer-by} ==> add the prefix by defined by user before the list of developers' logins