Onboard renovate

[michael-valdron]

What does this PR do?:

Adds initial renovate configuration to start creating Renovate patch PRs on the Llama stack upstream to ensure we maintain a good security score to bring into our product releases and keeps us on top of repeating maintenance.

Which issue(s) this PR fixes:

https://issues.redhat.com/browse/RHIDP-11200

PR acceptance criteria:

Testing and documentation do not need to be complete in order for this PR to be approved. We just need to ensure tracking issues are opened and linked to this PR, if they are not in the PR scope due to various constraints.

• Tested and Verified

• Documentation (READMEs, Product Docs, Blogs, Education Modules, etc.)

How to test changes / Special notes to the reviewer:

Run the following under a local pull of this branch to verify:

export GITHUB_COM_TOKEN=<github-rate-limit-token> # read-only token works
export LOG_LEVEL=debug

renovate --platform=local

[Jdubrick]

lgtm