Map of user replacements

## Background
Autoreplacemets can greatly simplify the work of the release notes creator, and improve the quality of generated release notes.

## Feature
Add a setting, which would be a map `string`->`string`. Each key occurence in the release notes entry would be replaced by its value in the draft

## Example usage
Contributor's name replaced for their GitHub handle
`David Benedeki->@benedeki `
Commonly mentioned projects or sites linked
`Fa-DB->[Fa-Db](https://github.com/AbsaOSS/fa-db)`