Starter kit v10.0.0 (and Bootstrap v5)

[ser9i0]

Please read and mark the following check list before creating a pull request (check one with "x"):

• [X] I read and followed the CONTRIBUTING.md guide.
• [X] I read and followed the New Feature Checklist guide.

Short description of what this resolves:

I wanted to use the starter-kit branch, but I saw it was still in v6.0.0, so I mixed the master branch (v10.0.0) with the starter-kit branch (and also updated the Bootstrap dependency to version 5).