macro driven Cortex Search and Agent deployment with externalized agent spec YAML.

This release primarily upgrades the deployment ease for Cortex Search and Cortex Agent services.
For Cortex Agent particularly, the dbt macro can now detect if agent exists and then run ALTER AGENT command instead of replacing with new Agent object. The Agent now also captures metadata through COMMENTs to include spec file name, auto-generated versions, update timestamp to allow for better traceability in production.

What's Changed

• Updates to Cortex Agent and Cortex Search deployments as managed through dbt macro ops. by @sfc-gh-clakkad in #9

Full Changelog: v2.0.0...v2.1.0