Create an obol-app chart suitable for making it easy to run an arbitrary docker image without knowing helm

[OisinKyne]

🎯 Problem to be solved

Not everything has a helm chart. Not everything needs a custom helm chart.

🛠️ Proposed solution

We can make a generic one, called obol-app and allow someone to use its values.yaml to control what arbitrary container to run, and what additional env vars and cli flags it should be passed. We can hardcode in the RPC URLS available (maybe with semi-standardised MAINNET_RPC_URL choices like foundry and others expect).

A stretch would be good decisions on how to mount files into this chart, and whether to have this chart or a separate one, focused on a webserver, where you don't even need to BYO-docker container, you give a js bundle or html or something and the chart serves it on the obol.stack/path it's asked to.

🧪 Tests

• Test steps or automation scripts are provided
• The chart is deployed to the test environment successfully

👐 Additional acceptance criteria

• The chart docs are updated
• The chart is released to live environments (if applicable)

❌ Out of Scope

The obol-webserver solution can come after this ticket which can focus on a docker container?

[OisinKyne]

Already implemented as obol-app, could do with a solution for local volume mounting