add build-in-devcontainer.yaml workflow

[trxcllnt]

Adds a build-in-devcontainer.yaml reusable workflow that can be used to build the code for a RAPIDS project in each of its devcontainers.

For example, here's how it would be used in RMM's pr.yaml, and here's the resulting devcontainer build matrix jobs:

  devcontainer:
    secrets: inherit
    uses: rapidsai/shared-action-workflows/.github/workflows/[email protected]
    with:
      build_command: |
        build-rmm-cpp -DBUILD_BENCHMARKS=ON
        build-rmm-python

Building the code in devcontainers in CI means the build cache is populated for developers, who are populating the build cache for CI, which is populating the build cache for developers... in an endless loop of build caching goodness.