[aom] Add new port

[HappySeaFox]

Describe the pull request

Add AV1 codec library

• What does your PR fix?

-

• Which triplets are supported/not supported? Have you updated the CI baseline?

Triplets: Everything except UWP and ARM.

CI baseline is not updated.

• Does your PR follow the maintainer guide?

Yes.

• If you have added/updated a port: Have you run ./vcpkg x-add-version --all and committed the result?

Yes.

[NancyLi1013]

Please also add dependency list if we use the suggested functions.

"dependencies": [
    {
      "name": "vcpkg-cmake",
      "host": true
    },
    {
      "name": "vcpkg-cmake-config",
      "host": true
    }
]

[HappySeaFox]

@Hoikas It looks like upstream delayed and de-prioritized the task to add CMake installation rules. Can we add CMake installation rules in the port as I did earlier with a patch? If it's not recommended, then I'm afraid we can close this PR.

[Hoikas]

That sounds good to me, I just think the namespace needs to be changed to unofficial to match the rest of the targets added in vcpkg. 😄