Add Arma 3 OCAP2 egg

[Freddo3000]

All Submissions:

• [x] Have you followed the guidelines in our Contributing document?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• [x] Did you branch your changes and PR from that branch and not from your master branch?

New Server Submissions:

1. [x] Does your submission pass tests (server is connectable)?
2. [x] Does your server use a custom docker image?
   • [ ] Have you tried to use a generic image?
   • [ ] Did you PR the necessary changes to make it work?
3. [x] Have you added the server to the main README.md?
4. [x] Have you added a unique README.md for the server you are adding?

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This image builds upon the OCAP2 web component Dockerfile, and thus uses a custom image. The source can be found here.

An example of it running can be found here.

[QuintenQVD0]

@Freddo3000 Please resolve or this will be closed