Add missing `@types` for used libraries

[Tristan-WorkGH]

Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines
• [ ] ~Tests for the changes have been added (for bug fixes / features)~
• [ ] ~Docs have been added / updated (for bug fixes / features)~

Does this PR already have an issue describing the problem?

No.

What kind of change does this PR introduce?

Add missing @types for used libraries, needed to develop correctly in Typescript.

What is the current behavior?

Dev without typescript definitions of libraries.

What is the new behavior (if this is a feature change)? .d.ts added

Does this PR introduce a breaking change or deprecate an API?

• [ ] Yes
• [x] No

If yes, please check if the following requirements are fulfilled

• [ ] ~The Breaking Change or Deprecated label has been added~
• [ ] ~The migration steps are described in the following section~

What changes might users need to make in their application due to this PR? (migration steps)

None.

Other information:

Had to keep @types/jest for tests to compile...