[c++] Add option to link installed spdlog lib

[XanthosXanthopoulos]

Issue and/or context: #3585 #3154 [sc-57301]

Changes:

Notes for Reviewer:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.35%. Comparing base (bd6b6cd) to head (1ff45c9).
Report is 3 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #3698       +/-   ##
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+ Coverage   65.53%   86.35%   +20.81%     
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  Files         151       55       -96     
  Lines       19427     6494    -12933     
  Branches     1164        0     -1164     
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- Hits        12732     5608     -7124     
+ Misses       6292      886     -5406     
+ Partials      403        0      -403     

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Components	Coverage Δ
python_api	86.35% <ø> (+0.03%)	⬆️
libtiledbsoma	∅ <ø> (∅)

[jdblischak]

Nice @XanthosXanthopoulos!

I am testing SPDLOG_LINK_SHARED=ON in my feedstock fork:

https://github.com/jdblischak/tiledbsoma-feedstock/compare/test-spdlog-link-shared
jdblischak/tiledbsoma-feedstock@0066dda

xref: TileDB-Inc/tiledbsoma-feedstock#252

[jdblischak]

I am testing SPDLOG_LINK_SHARED=ON in my feedstock fork:

I still got the same linking WARNING from conda-build after setting SPDLOG_LINK_SHARED=ON:

jdblischak/tiledbsoma-feedstock@3b7e6ff

WARNING (libtiledbsoma): run-exports library package conda-forge/linux-64::fmt==11.0.2=h434a139_0 in requirements/run but it is not used (i.e. it is overdepending or perhaps statically linked? If that is what you want then add it to `build/ignore_run_exports`)
WARNING (libtiledbsoma): run-exports library package conda-forge/linux-64::spdlog==1.15.1=hb29a8c4_0 in requirements/run but it is not used (i.e. it is overdepending or perhaps statically linked? If that is what you want then add it to `build/ignore_run_exports`)