Add custom docker pipeline for multiarch builds

[nkierpiec]

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Chore (non-breaking change that does not add functionality or fix an issue)

Checklist:

• I have read the CONTRIBUTING document.
• I have run the pre-merge tests locally and they pass.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.
• All commits have been signed-off for the Developer Certificate of Origin.

[jeremiahsnapp]

This looks really awesome! I just have a couple comments.

[mimaslanka]

Suggest that we move this to a function

function create_and_push_manifest ()  {
     echo "---  Creating..."
     docker manifest create ${1}:${2}" \
         --amend ${1}:${EXPEDITOR_VERSION}-arm64 \
         --amend ....-amd64

     echo "--- Pushing...."
     docker manifest push....
}
create_and_push_manifest "chef/chef" "${EXPEDITOR_TARGET_CHANNEL}"
 
if ....
   create_and_pus_manifest "chef/chef" "latest"
  ...