Add reactor

[moritzn-met]

Goal

Add reactor component. (Fix #476) Its an additional component, I didnt manage to extend this to use for Steam Generator. (BC of different design, and purge)

Type of change

• Bugfix
• New feature
• Refactoring change
• Release & Version Update (don't forget to change the version number in package.mo)

Will it break anything in previous models ?

• Breaking change (If yes, make sure to point it out in the changelog)
• Non-Breaking change

Checklist

• I have added the appropriate tags, reviewers, projects (and detailed the size and priority of my PR) and linked issues to this PR
• I have performed a self-review of my own code
• I have checked that all existing tests pass.
• I have added/updated tests that prove my development works and does not break anything.
• I have made corresponding changes or additions to the documentation (in Notion documentation)
• I have added corresponding entries to the Changelog
• I have checked for conflicts with target branch, and merged/rebased in consequence

You can also fill these out after creating the PR, but make sure to check them all before submitting your PR for review.

[hadrienp-met]

I think you forgot to add the test models to your commit, the "Add tests" has no changes to show

[moritzn-met]

I think you forgot to add the test models to your commit, the "Add tests" has no changes to show

Ups yeah something went wrong. I added the tests!

[hadrienp-met]

A few comments, but it looks good to me

[hadrienp-met]

Don't forget to update the changelog and add the component to the documentation

[hadrienp-met]

You need to update the changelog