Remove requirements.txt contents and point to datadog-agent-buildimages

[mx-psi]

What does this PR do?

Replace current requirements.txt file with the latest version of the datadog-agent-buildimages requirements.txt file.

Motivation

We want to install dependencies on the images at build time to reduce the amount of network errors, while still keeping existing contributing instructions simple.

Additional Notes

This should be a no-op.

Reviewer's Checklist

• If known, an appropriate milestone has been selected; otherwise the Triage milestone is set.
• The appropriate team/.. label has been applied, if known.
• Use the major_change label if your change either has a major impact on the code base, is impacting multiple teams or is changing important well-established internals of the Agent. This label will be use during QA to make sure each team pay extra attention to the changed behavior. For any customer facing change use a releasenote.
• A release note has been added or the changelog/no-changelog label has been applied.
• Changed code has automated tests for its functionality.
• Adequate QA/testing plan information is provided if the qa/skip-qa label is not applied.
• If applicable, docs team has been notified or an issue has been opened on the documentation repo.
• If applicable, the need-change/operator and need-change/helm labels have been applied.
• If applicable, the config template has been updated.

[paulcacheux]

Hello ! Is this really a no-op ? For example a new developper running pip install -r requirements.txt at the root of the repo will get an error. This is a required step for a new environment since it installs invoke

[mx-psi]

For example a new developper running pip install -r requirements.txt at the root of the repo will get an error

No, a new developer should not see any changes. We keep the requirements.txt file, but make it so if you do pip install -r requirements.txt you are actually installing the requirements from datadog-agent-buildimages.

[paulcacheux]

Oh you are right ! I completely misunderstood the -r feature, sorry about that

[mx-psi]

No worries, it was a valid concern :)