Refactors topdown service to support multiple types of calculations and adds support for Sapphire Rapids

[ilumsden]

This PR refactors the topdown service to allow it to be easily extended to support top-down calculations for processors besides Haswell/Broadwell. To do this, I've made the following changes:

• Creates a new TopdownCalculator base class to represent calculations for different processors
• Moves the existing calculations to a new HaswellTopdown class, which inherits from TopdownCalculator
• Refactors IntelTopdown to offload all the computation and associated tracking to a pointer to a TopdownCalculator object

This PR also uses this new infrastructure to add support for Sapphire Rapids and Emerald Rapids CPUs. The calculations for these CPUs were obtained from Intel's perfmon repo, specifically the following file: https://github.com/intel/perfmon/blob/main/SPR/metrics/perf/sapphirerapids_metrics_perf.json. The support added by this PR only covers the first two levels of the top-down hierarchy. In the future, this could be expanded to cover as much of the 6 levels for Sapphire Rapids as desired.

This PR is still work-in-progress. The following tasks need to be completed before this is ready for review:

• Add a CMake mechanism to specify an architecture (currently planning on supporting architecture names from archspec)
• Use that mechanism to select (at build time) the correct TopdownCalculator child class to use in the topdown service
• Examine if any changes need to be made to the topdown built-in option

[ilumsden]

In the future, it might be useful to consider embedding archspec-json if more architecture-specific features are added to Caliper.

[ilumsden]

Outstanding work on this PR:

• Find a way to use PAPI multiplexing with the SPR counters needed for topdown
• Add testing
• Update documentation (if it exists) about the topdown service