Refactored Exam Agent

[QcFe]

Description

This PR slightly refactors the Exam Agent for the rendering part through the following improvements:

• better error handling
• json/html support
• authenticated instances listing

[kingmakerbot]

Hi @QcFe. Thanks for your PR.

I am @kingmakerbot. You can interact with me issuing a slash command in the first line of a comment. Currently, I understand the following commands:

• /rebase: Rebase this PR onto the master branch
• /merge: Merge this PR into the master branch
• /hold: Adds hold label to prevent merging with /merge
• /unhold: Removes the hold label to allow merging with /merge
• /deploy-staging: Deploy a staging environment to test this PR
• /undeploy-staging: Manually undeploy the staging environment

Make sure this PR appears in the CrownLabs changelog, adding one of the following labels:

• kind/breaking: :boom: Breaking Change
• kind/feature: :rocket: New Feature
• kind/bug: :bug: Bug Fix
• kind/cleanup: :broom: Code Refactoring
• kind/docs: :memo: Documentation

[kingmakerbot]

The go.mod and/or go.sum files appear not to be correctly tidied.

Please, rerun go mod tidy to fix the issues.

[kingmakerbot]

The generated files in the operators/ folder appear to be out-of-date.

Please, ensure you are using the correct version of controller-gen and re-run:

make generate
make manifests

Here it is an excerpt of the diff:

```diff ```

[QcFe]

/merge