Resolve config and configurable model aspects by template path, not by compilation entrypoint path

[jeskew]

Resolves #8046

This change impacts much larger number of files than initially expected, mostly because we use the Compilation constructor frequently in test packages. The language server keeps uses a file watcher to keep an in-memory cache synced, to report telemetry on config changes, and to recompile active contexts on configuration changes, and that behavior needed to be integrated into the configuration manager passed to the Compilation objects (since configuration resolution now happens for each bicep file that is loaded, not just the entrypoint model).

Microsoft Reviewers: Open in CodeFlow