Instructions for running CI tests locally via Docker do not work

[psx95]

Based on the current instructions for running the CI tests locally, I should be able to run

./ci/run_docker.sh 

from the root of the project to enter a docker shell where I can run tests manually.

However running this command results in an error

unable to prepare context: unable to evaluate symlinks in Dockerfile path /Projects/opentelemetry-cpp/ci/Dockerfile: no such file or directory

This is probably coming from this line in the shell script which seems like it is explicitly looking for a Dockerfile in the ci directory and currently there is none.

[esigo]

@psx95 I added documentation for devcontainer here https://github.com/open-telemetry/opentelemetry-cpp/blob/ce1e82a8bfe71ae814f6e1d219515b94560ea6ce/CONTRIBUTING.md#devcontainer-setup-for-project

[dbarker]

As a new contributor I initially hit this issue and manually copied .devcontainer from #3123 to test my PRs locally. It's been very helpful.

In addition to the ./ci/run_docker.sh script not working as mentioned above. The targets for do_ci.sh seem to have changed and documentation needs to be updated. For example ./do_ci.sh cmake.maintainer.test doesn't work but other maintainer test targets do (cmake.maintainer.sync.test among others).

Happy to help on documentation or testing for the PR if needed.