Update READMEs with minimum Agent versions

[dkirov-dd]

What does this PR do?

Adds an indication for the minimum Agent version that includes each integration inside of each respective README.

Motivation

Users should be able to tell at a glance whether or not their Agent comes with a given integration they wish to use.

Notes

The integration versions were derived from the CHANGELOG.md entries of each integration.

The integrations who's 1.0.0 version was not annotated with an Agent version -- due to them being released before those annotations were instrumented in the release process -- have their corresponding Agent version determined by matching the earliest Agent release date (featured here) following the integration release date.

Integrations released before Agent 6 indicate 6.0.0 as their minimum Agent version. This should be sufficient as this change is aimed at new users.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[github-actions]

⚠️ Recommendation: Add qa/skip-qa Label

This PR does not modify any files shipped with the agent.

To help streamline the release process, please consider adding the qa/skip-qa label if these changes do not require QA testing.

[tbavelier]

LGTM for @DataDog/container-ecosystems file (operator integration)