Tooling Prep for Increase in Configurations Supported

[wchilders-nvidia]

In preparation for adding more build types and testing configurations I've prepared these changes:

• New AGENT.md skill for working with edg-cmakedef.
• New AGENT.md skill for creating temporary files and working around the container environment efficiently.
• Disable eccp's injection of automatic template instantiation flags (as part of eccp's processing of the --building_runtime option) for the runtime library build so that configurations that don't support automatic template instantiation can still build the library.
• Detect and skip tests for which a command-line "mode" flag was required that is not supported by the current configuration (e.g., "--microsoft" implies the config must have MICROSOFT_EXTENSIONS_ALLOWED).
• And the bigger one: expectation inheritance. Expectations are now inherited in the same way that default outputs are inherited, meaning that expectation updates in the default configuration flow down to child configurations (i.e. if a test is failing in the default, it's expected that it will be failing in the non-default). Thus, non-default configuration expectation files now become deltas against the default configuration. This significantly reduces the number of tests that need to be run on average, because for many many cases, configurations will all agree on the outcome.

Reviewed internally by @nv-cmeerw

[mborland]

Since this makes three tooling PRs open (#237 and #246), do you want to merge those first, or pull them into this one? On a cursory look I don't think there are many conflicts between the first two and this one, but they may start to diverge in contents (e.g. pinned docker hashes).

[wchilders-nvidia]

I need to look at #237; shouldn't be blocked or a blocker for this one.

#246 I need to get back to but this is arguably more important as without it downstream maintenance is more costly and certain configurations just don't work well with the build system.

[mborland]

Looks good to me. I've found a couple issues when attempting to build and test everything on ARM64 Mac, so this should help