Implement Metadata for SMAC enabling Multi-Fidelity

[jsfreischuetz]

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Enables changing the defaults in the SMAC optimizer to enable state passing (what SMAC internally calls context, but that doesn't match MLOS's notion of context) and multi-fidelity tuning.

This required a few additional changes to metadata throughout the project

Additionally, this PR includes a test case for Multi-Fidelity Tuning

This PR replaces the previous one (https://github.com/microsoft/MLOS/pull/751)