Generate buildspec.yml to publish images to AWS Public ECR (#452)

* add buildspec with test image to publish

* update env variables

* update account id variable

* update docker command with image type

* update image and tag with proper structure for ecr repos

* update to publish to public ecr

* fix docker tag

* update for public ecr login

* update aws ecr public and private and log aws version

* add check for finding published ecr image

* update to be batch-list build

* update identifier

* update build-list syntax

* fix build-list syntax

* add node12.18.4-edge88 to build list

* update build-list syntax

* separate to use buildspec-build-list

* update identifiers

* update identifiers

* exit 1 if found

* move back into single buildspec.yml

* add public echo

* run describe-images for debugging

* cleanup

* install slugify

* wip - iterate on aws codebuild config generate

* generate base image list

* generate browsers images to buildspec.yml

* generate buildspec config for included

* update to skipBrowserImages for buildspec

* refactors

* install via npm

* namespace ecr repos

* add IMAGE_DIR to buildspec

* update to use production ecr alias

* temporarily publish base in buildspec

* restore browsers to buildspec

* restore included to bulidspec

* run generate config and add included 6.5.0 to buildspec