Resolve "Docker Builds are not able to provide a tag version"

General MR

Summary

Extracts out the docker builds from pipeline-templates.yaml and bigbang-infra.yaml to make single, reusable image-build.yaml pipeline. These dockerfiles have been moved to it's own subgroup.

Once this MR is merged, then we can merge the subsequent MRs for each docker repo:

• working main pipeline with auto tag
• terraform
• cypress
• bb-ci
• atlantis in progress

Relevant logs/screenshots

(Include any relevant logs/screenshots)

Linked Issue

Closes #372

Blocks: #375 #377 #374 #376

Upgrade Notices

N/A

Closes #372