Add docker package for Mongo 6

[Lysoun]

⚠️ Mongo cli is not usable with mongo 6, only mongosh The mongo shell may already be available in mongo 6 images, a test should be done

Things to do:

• add mongo 6 in AbstractMongoDbTest and ensure the IT tests do pass (the CI can do it if you just push)
• add a Dockerfile for mongo 6

If this issue is taken by someone outside of the maintainers team, please set the branch 2.1 as the destination branch for your PR