CMake updates

[ViliusSutkus89]

Hello,

Thanks for the library. I'm trying to use it through CMake, but I've noticed a couple of lines that could be added there.
I've changed to version number, to match the actual current number - 0.8.2.
Added install command, to allow running cmake install, which installs the library and public headers from included directories.
Directories are added to the search path using target_include_directories, so there's no need to add them using CFlags.
64 bit ARM architecture can be defined as aarch64, so I've added that to the if statement, which selects arch folder.

I've also added BUILD_SHARED_LIBS option. In this regard, this patch does the same as @theoparis suggested in #299, but according to CMake docs, the option string is also needed. The resulting add_library call is the same, so both PR's should be able to merge.

I've tried running the changes in CI, but somewhy windows clang64 errors about complaining about missing gcc. I haven't touched that part, so I assume the CI should error out without these changes too

Regards,
Vilius

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 39.02%. Comparing base (4b83beb) to head (2899a5e).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #302      +/-   ##
==========================================
+ Coverage   38.24%   39.02%   +0.78%     
==========================================
  Files         233      233              
  Lines        6139     6144       +5     
  Branches     1607     1608       +1     
==========================================
+ Hits         2348     2398      +50     
+ Misses       3394     3393       -1     
+ Partials      397      353      -44     

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