We currently have a bunch of build dependencies that we need in order to produce proxy builds and which we have to build and manage ourselves. We should include those builds in CPaaS to make it easier for the team to track them and update their versions as required.

Relevant packages are (probably incomplete?):

• bazel
• ninja-build
• binaryen
• emsdk
• gn

Acceptance Criteria:

• add all build deps that we manage to our CPaaS instance, possibly on their own branch, with a separate build pipeline (as they need to be already present when running the main pipeline)
• update CPaaS setup document