Improve docker build times

[adzialocha]

Some ideas:

• Move all docker images from Digital Ocean to a public repository (we have to change all the tagbuild.yaml github actions and change the image urls in the circles-iac Helm charts)
• Use these images in our circles-docker repo instead, they are already built and faster to use
• Change the Makefile to support a different API, something like:

# This will build your local versions of the circles-api and safe-relay-service
make build api relayer

# This will use all pre-built images from the public repository
make build