[WIP] policy: refactor of policy options and matching

[wihobbs]

Problem: the current matching functions for config-provided policies don't take advantage of some C++20 features, are a bit confusing, and have no unit tests.

Refactor and add unit testing.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 86.66667% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 73.9%. Comparing base (bb686df) to head (228e1b7).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #1192 +/- ## ======================================== - Coverage 73.9% 73.9% -0.1% ======================================== Files 102 103 +1 Lines 14565 14576 +11 ======================================== + Hits 10766 10773 +7 - Misses 3799 3803 +4 ``` | [Files](https://app.codecov.io/gh/flux-framework/flux-sched/pull/1192?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flux-framework) | Coverage Δ | | |---|---|---| | [resource/policies/dfu\_match\_policy\_factory.cpp](https://app.codecov.io/gh/flux-framework/flux-sched/pull/1192?src=pr&el=tree&filepath=resource%2Fpolicies%2Fdfu_match_policy_factory.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flux-framework#diff-cmVzb3VyY2UvcG9saWNpZXMvZGZ1X21hdGNoX3BvbGljeV9mYWN0b3J5LmNwcA==) | `92.1% <100.0%> (-0.8%)` | :arrow_down: | | [...licies/base/test/matcher\_policy\_factory\_test02.cpp](https://app.codecov.io/gh/flux-framework/flux-sched/pull/1192?src=pr&el=tree&filepath=resource%2Fpolicies%2Fbase%2Ftest%2Fmatcher_policy_factory_test02.cpp&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=flux-framework#diff-cmVzb3VyY2UvcG9saWNpZXMvYmFzZS90ZXN0L21hdGNoZXJfcG9saWN5X2ZhY3RvcnlfdGVzdDAyLmNwcA==) | `73.3% <73.3%> (ø)` | |