AthContainers: Switch to using ThinningInfo for the lossy float compression inside copyAuxStoreThinned

This MR builds on !35444 (merged). With this MR we're switching to using ThinningInfo to determine whether lossy float compression should be applied to a given AuxID and apply it in copyAuxStoreThinned. Parts that refer to the now-defunct IAuxStoreCompression are completely removed. The next step is to completely get rid of this interface and its implementation in AuxContainerBase.

One key item that was previously missing was a regression test that ensures the lossy float compression is applied correctly. copyAuxStoreThinned_test is extended to address that problem. Since by default we don't yet compress anything, the changes should be transparent to existing workflows. However, I'm asking for full-unit-tests to make sure there are no unintended side effects.

The next step will be cleaning up the previously implemented infrastructure as noted above.

cc: @ssnyder @mnowak @gemmeren

Control/AthContainers/AthContainers/tools/copyAuxStoreThinned.h

@@ -40,6 +40,18 @@ void copyAuxStoreThinned (const SG::IConstAuxStore& orig,
                           SG::IAuxStore& copy,
                           const SG::ThinningInfo* info);
 
+/**
+ * @brief Helper method to apply lossy float compression
+ * @param dst Pointer to the start of the vector's data
+ * @param idst Index of element in vector
+ * @param eltSize Element size for the auxid
+ * @param typeName Type name for the auxid
+ * @param nmantissa Compression level to be used for the auxid
+ */
+void lossyFloatCompress (void* dst, std::size_t dst_index,
+                         const std::size_t& eltSize,
+                         const std::string& typeName,
+                         const unsigned int& nmantissa);
 
 } // namespace SG