after migration is done & working well, clean all the remaining things:

wait!! we can't do most of this ATM because FedRAMP relies on these builds

app-interface

• remove old jenkins build jobs
• remove old jenkins job-template ("ocm deploy ...")
• clean up possible residue definitions for sentry-integration

uhc-portal

• remove push_to_insights.sh
  make sure to switch off webhooks beforehand, and/or remove the corresponding jobs from app-interface (ocm-portal-deploy*).- cannot be done ATM, see reasoning in OCMUI-2098
• make sure sentry version and flow is implemented elsewhere, or port it (done in OCMUI-2034)
• in package.json remove the old impl' of build:prod and its derivatives, and rename build:sass et. al. to build:prod etc. cannot be done ATM, due to OCMUI-2098
• in deploy_info.mjs, update envs values (e.g. pipeline URLs), and remove redundant ones
• update README files which reference other removed files
• TODO - find more things to clean