[openedx/enterprise-subsidy] Dockerfiles and Workflow setup for Dev environment

[UsamaSadiq]

Description

• Issue created under the implementation of https://github.com/edx/edx-arch-experiments/issues/587

### Tasks
- [x] Move the `Dockerfile` and `push-docker-image.yml` files present in the IDA to public-dockerfiles repository
- [x] Schedule the workflow to run once a day to build and publish dev image to [docker.io/edxops](http://docker.io/edxops) org
- [x] Add `workflow_dispatch` option to provide option to trigger the workflow manually if required
- [x] Setup email alert in case the workflow fails in building and publishing the image to notify the owning team in case of failure
- [x] Test the workflow once on pull request to verify everything is working as expected
- [ ] Update the devstack references to pull the image from the updated host organization if needed
- [ ] Update the GoCD pipeline code to reference Dockerfile from the updated path in `public-dockerfiles` repository
- [ ] Remove the Dockerfiles and workflow files from the source IDA repository

[UsamaSadiq]

PR https://github.com/edx/public-dockerfiles/pull/28 merged for this issue.

[BilalQamar95]

Removed the Dockerfile and workflow files from source IDA: https://github.com/openedx/enterprise-subsidy/pull/313