Removing dependencies to speed up startup

[hubertp]

Pull Request Description

Reducing the number of dependencies. Explicit cats are almost gone (present in cli). enumeration is completely gone. cats is also still included implicitly via io.circe but that's a different kind of beast. Also, really removed jackson from dependencies by fixing the dependency on http-test-helper.

Important Notes

In a number of places importing all cats implicits could be simply replaced with a single or two method calls. Not to mention that this will reduce compilation times due to reduced implicit search space.

One example of how the changes affect performance (not only startup):

Before: Now: (frequently executed)

Also appears to be gone.

This PR is by no means finished. The purge will continue in follow up PRs.

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• [ ] The documentation has been updated, if necessary.
• [ ] Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• [x] All code follows the Scala, Java, TypeScript, and Rust style guides. In case you are using a language not listed above, follow the Rust style guide.
• [ ] Unit tests have been written where possible.

[hubertp]

I liked the other PR title more but it wasn't descriptive enough.