Revise design for optional features and AOT

[gmlueck]

Revise the design for handling optional kernel features for AOT compilations. There is no need to create a separate tool "aspect-filter" because the filtering can be done in the "sycl-post-link" tool instead. This is better aligned with our long term direction because "sycl-post-link" will need to do some AOT-specific IR transformations in the future as part of the design presented in #9127, and those transformation will also make use of the device configuration file.

This commit also addresses some issues that were missed before related to embedding several AOT-compiled offload bundles into the host executable.