Don't override DMR endpoint when inside a container

[mikesir87]

Describe the bug

The DMR provider currently sets the endpoint to use localhost:12434, even when inside a container. It would be great to see if the /.dockerenv file exists and use that to determine if the override should occur.

Version affected

1.0.6

How To Reproduce

1. Start a container with cagent inside it.
2. Use the DMR provider
3. Notice it uses localhost:12434 by default.

Expectation

I'm in a container, so it should use the default model-runner.docker.internal or use the value of MODEL_RUNNER_HOST.

[krissetto]

Now cagent will:

• check for the MODEL_RUNNER_HOST, if it exists use that
• check if we're in a docker container (checking for /.dockerenv), if so it won't override the output of docker model status command
• if the env var is not present, and we're not in a container, then override