Add token variations to transform the output to uppercase, lowercase and capitalize

Problem/Motivation

Currently in several notifications we use placeholders to show the entity type (Topic, Event, Comment etc). We force this placeholders to always be lowercase. This works well in english and most languages, but not in German for example where those terms should be displayed uppercase.

Proposed resolution

Add variations to transform the output of some tokens to lowercase, uppercase and capitalize.

Remaining tasks

N/A

User interface changes

N/A

API changes

N/A

Data model changes

N/A