[Compiled Scripts] Add healthcheck for loading capabilities

When using precompiled scripts, the information about the scriptlets are exposed by the bundle using capabilities. These capabilities are loaded async, and it's unclear when the loading process is completed (no log statement indicating this).

We should have a healthcheck which exposes the information, that processing of capabilities is ongoing (or not). This combined with the information that all bundles are active should give a good indication, if it's safe to start request handling.