chat-core: convert into monorepo, update configuration

[popestr]

Converts the chat-core repo into a monorepo, in anticipation of implementation of the AWS Connect flavored package.

TEST=auto

Built and ran tests, will ensure GH actions pass.

[semgrep-app]

Legal Risk
The following dependencies were released under a license that is currently prohibited by your organization. Merging is blocked until this is resolved.
Recommendation:
Reach out to your security team or Semgrep admin to address this issue. In special cases, exceptions may be made for dependencies with violating licenses, however, the general recommendation is to avoid using a dependency under such a license

MPL-2.0
turbo 1.13.4
turbo-darwin-64 1.13.4
turbo-darwin-arm64 1.13.4
turbo-linux-64 1.13.4
turbo-linux-arm64 1.13.4
turbo-windows-64 1.13.4
turbo-windows-arm64 1.13.4

[popestr]

Semgrep is failing due to MPL-2.0 being unapproved. This license (for the same package, turbo) has already been approved for the chat-headless repo, so we are okay to merge past this failure. On merge, this license will be approved for this repo as well.