Generating protobuf at container build time

[fsolleza]

Changes

Problem:

Small changes to protobuf require extensive tooling to generate protobuf using make generate-protobuf. ide-gen-proto.sh shows how some service's protobuf might be generated.

Four services' generated protobuf code were moved to container build time. This doesn't replace make generate-protobuf which is still useful when understanding the protobuf code outside of build time. It makes make start and friends friendlier to small changes to pb/demo.proto.

The four services affected are:

1. accountingservice
2. checkoutservice
3. productcatalogservice
4. currencyservice

Solution is discussed in-depth in #1374

Merge Requirements

For new features contributions please make sure you have completed the following
essential items:

• CHANGELOG.md updated to document new feature additions
• Appropriate documentation updates in the docs
• Appropriate Helm chart updates in the helm-charts

Maintainers will not merge until the above have been completed. If you're unsure
which docs need to be changed ping the
@open-telemetry/demo-approvers.

[linux-foundation-easycla]

• ✅ login: fsolleza (810a9f7)
• ❌ The email address for the commit (dfaf53f, 8fa8071, f03cad7, f013835) is not linked to the GitHub account, preventing the EasyCLA check. Consult this Help Article and GitHub Help to resolve. (To view the commit's email address, add .patch at the end of this PR page's URL.) For further assistance with EasyCLA, please submit a support request ticket.

[puckpuck]

@fsolleza please sign the CLA when you get a chance

[fsolleza]

Hmm - I'm unfamiliar with this process but I've signed the CLA (or so I think).

[austinlparker]

Seems like there's still an issue with the CLA (see #1384 (comment)) -- is the email associated with the commits different than the one that you signed the CLA with? You may need to squash your commits locally and force push the branch to resolve this.

[fsolleza]

Ok, I'm gonna retry with another pull request with hopefully the correct email address. It's small enough to easily just recreate from a clean branch tracking upstream.