Moved the integration sections into a separate component

What does this MR do and why?

This is the next step in the Refactor the architecture of the integration_fo... (#382796) effort. This time, we move the form's sections into a separate component to be able to make it modular on the next step and allow different integrations define their sections separately instead of tossing everything into one component as you can see in the section.vue where we dynamically load components for Jira even though it's a universal form and should be particular-integration-agnostic.

Screenshots or screen recordings

No visual changes should be observed. Here are a couple of integrations to confirm the point

	Before	After
Jira integration
Slack notifications integration

How to set up and validate locally

If you have any integration available locally, make sure it still works as it should.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #382796