Updates to overlay standards used by scripts

[l-monninger]

Summary

In order to facilitate better documentation of overlays and better namespacing, we propose two changes to the just <application> <docker-compose|native> <overlays> scripts:

1. Have the scripts look up into a directory named with the overlay.
2. Have the tests reside in a special directory tests which then contain individual overlays.

Overlays in individual directories

Currently, the scripts look up application overlays as follows:

1. Look for a folder named <application> in a directory named <docker-compose|native> which is at a well-known path from the repository root. That is, ./well/known/path/<docker-compose|native>/<application>.
2. Merge in the base overlay for the composed application, e.g., process-compose.yml or docker-compose.yml that is found in the folder. That is, for example, ./well/known/path/<docker-compose|native>/<application>/process-compose.yml.
3. Merge in the overlay files marked by overlay names separated with a .. Each overlay would correspond with a file containing its suffix. For example, the eth-local process-compose overlay for the Suzuka Full Node would correspond to a file at ./well/known/path/native/suzuka-full-node/process-compose.eth-local.yml

We propose a change to 3 above, that would instead place the eth-local file at ./well/known/path/native/suzuka-full-node/eth-local/process-compose.yml

Pros:

• Most importantly this allows us to more deeply document each overlay without introducing a massive top-level README. That is, we can, for example, place a ./well/known/path/native/suzuka-full-node/eth-local/README.md.
• Generally, we can extend the above pattern to other conveniences.

Designated tests namespace

Currently, tests are written as common overlays. We propose instead a dedicated namespace with its own subdirectories be pulled out.

This would introduce a standard such that each application target would at least have the following structure:

/my-application
    docker-compose.yml
    /tests

In the case of the, test-followers test from Suzuka, this would be reorganized to:

/suzuka-full-node
    /tests
       /followers
          README.md
          process-compose.yml

A special syntax can likewise be adopted to indicate when addressing this namespace, such as separating the feature string with a :. For example:

just suzuka-full-node native build.setup.eth-local.celestia-local.tests:followers

This syntax could provide the basis for further namespace extensions in the future, though it may be better to restrict to just the tests versus standard overlays distinction.