Refactor docker support and add web-searcher image

[huangyingting]

Motivation and Context

1. Why is this change required? Refactor docker support to reflect recent configuration changes and add web-searcher docker image support.
2. What problem does it solve? Refactor docker support to reflect recent configuration changes and add web-searcher docker image support.
3. What scenario does it contribute to? Local docker developerment with docker-compose support
4. If it fixes an open issue, please link to the issue here. N/A

Description

1. Reflect recent configuration changes to use .env files for configuration rather than baking in values. Add an .env.example file to the docker directory to serve as a template. Keep the refactored docker config isolated in the docker directory to avoid impacting the original configuration.
2. Add docker configuration and image build support for the new web-searcher plugin.
3. Update the copilot-build-image workflow to also build the web-searcher docker image.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[Ryangr0]

Really nice, this is almost 1:1 what I have for my application that builds on top of chat copilot. Env vars are the way to go. I have a question about the search. I've played around with this kind of idea in the past, and something I got to work with Langchain was searxng. Searxng is good, because it's open sourcem, free, keeps "you" anonymous and it's able to aggregate search results across different search engines. And it layers between your service and for example google, meaning that you don't need to pay for API access to their search.

This is what I had the service look like in my docker-compose.yml

searxng:
    container_name: searxng
    image: searxng/searxng:latest
    ports:
     - "8080:8080"
    volumes:
      - ./searxng:/etc/searxng:rw
    environment:
      - SEARXNG_BASE_URL=http://localhost:8080/
    cap_drop:
      - ALL
    cap_add:
      - CHOWN
      - SETGID
      - SETUID
    logging:
      driver: "json-file"
      options:
        max-size: "1m"
        max-file: "1"

[glahaye]

This PR leaves the previous Docker-related files in place, creating duplicates.

Please either modify the files that already exist, or delete them.

[huangyingting]

Done review and removed old files.