build system and module refactoring + simple histogram scratch (#20)

* scratch adding histogram to image views

Histograms should come from some sort of histogram service. This is
currently just a POC.

* custom logger implementation w/o spdlog

* missing cmake file

* fix tests

* use operator<< over direct stream exposure

* rm print header

* add threading test + refactor towards interface libraries

omits the need for =target_include_directories= calls /everywhere/

* rm print header

* rm constexpr

* templated thread_pool

* fix doxyfile

* default enable doc building

* czi reader refactor

* rm erroneous include expression

* clang-format

* single lib include with PUBLIC visibility

* compile imgui stdlib

* clang format

* documentation update

centralize `LogLevelToString` to `ILog.hpp`

update docs and examples

cmake/libCZI.cmake

@@ -4,6 +4,7 @@ FetchContent_Declare(
   libCZI
   GIT_REPOSITORY https://github.com/ZEISS/libczi.git
   GIT_TAG        main
+  DOWNLOAD_EXTRACT_TIMESTAMP 1
 )
 
 if(NOT libCZI_POPULATED)