chore: update mermaid files

[FaGru3n]

Description

As is seen you have forgotten some diagram files created one that i found to help you how it could look like.

• update mermaid files with correct ending
• add DataModelv6 as mermaid file

updates #91

Pre-review checks

Please ensure to do as many of the following checks as possible, before asking for committer review:

• DEPENDENCIES are up-to-date. Dash license tool. Committers can open IP issues for restricted libs.
• Copyright and license header are present on all affected files

[fabiodmota]

LGTM , thanks for the work