Cleanup shared references

[Kielek]

Fixes #1430 (comment)

Changes

Drop most of the Shared properties.
The only exception if for IncludeSharedSpanHelper. There are two independent copies of similar files. I have a plan to solve it in follow up pr.

For significant contributions please make sure you have completed the following items:

• [ ] Appropriate CHANGELOG.md updated for non-trivial changes
• [ ] Design discussion issue #
• [ ] Changes in public API reviewed

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.84%. Comparing base (71655ce) to head (7c2061b).
Report is 154 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1595      +/-   ##
==========================================
- Coverage   73.91%   72.84%   -1.07%     
==========================================
  Files         267      258       -9     
  Lines        9615     9392     -223     
==========================================
- Hits         7107     6842     -265     
- Misses       2508     2550      +42     

Flag	Coverage Δ
unittests-Exporter.Geneva	58.17% <ø> (?)
unittests-Exporter.OneCollector	89.46% <ø> (?)
unittests-Extensions	82.75% <ø> (?)
unittests-Instrumentation.AspNet	75.96% <ø> (?)
unittests-Instrumentation.EventCounters	75.92% <ø> (?)
unittests-Instrumentation.Owin	85.71% <ø> (?)
unittests-Instrumentation.Process	100.00% <ø> (?)
unittests-Instrumentation.Runtime	100.00% <ø> (?)
unittests-Instrumentation.StackExchangeRedis	68.02% <ø> (?)
unittests-Instrumentation.Wcf	78.47% <ø> (?)
unittests-PersistentStorage	58.80% <ø> (?)
unittests-ResourceDetectors.Azure	81.53% <ø> (?)
unittests-ResourceDetectors.Host	40.00% <ø> (?)
unittests-ResourceDetectors.Process	100.00% <ø> (?)
unittests-ResourceDetectors.ProcessRuntime	76.08% <ø> (?)
unittests-Solution	79.49% <ø> (?)

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see 208 files with indirect coverage changes

[Havret]

lgtm +1