[INFRA] Simplify

[eseiler]

• datasources: Auto add everything in test/data
• datasources: Add example for external datasource (download)
• above: needed?
• Do we need interface + lib?
• more cleanup :)
• simplify CI/make things optional (e.g., coverage)

Questions regarding output:

• bin is empty, binary is in build directory
• lib is not empty, gtest is there. app-template lib is in build directory

Is this OK, or would it be better to do bin/lib output dirs again?

Current output:

As picture Click

As text Click

~/develop/app-template/build/GCC-13-Debug$ tree -L 2
.
├── CMakeCache.txt
├── CMakeFiles
│   ├── 3.28.3
│   ├── [...]
│   └── progress.marks
├── CPM_modules
│   ├── FindGTest.cmake
│   ├── Findcereal.cmake
│   ├── Findhibf.cmake
│   ├── Findseqan3.cmake
│   ├── Findsharg.cmake
│   ├── Findsimde.cmake
│   └── Findyaml-cpp.cmake
├── CTestTestfile.cmake
├── Makefile
├── _deps
│   ├── cereal-build
│   ├── gtest-build
│   ├── hibf-build
│   ├── seqan3-build
│   ├── sharg-build
│   ├── tdl-build
│   ├── tdl-subbuild
│   └── yaml-cpp-build
├── app-template
├── bin
├── cmake_install.cmake
├── compile_commands.json
├── cpm-package-lock.cmake
├── lib
│   ├── libgtest.a
│   └── libgtest_main.a
├── libapp-template_lib.a
└── test
    ├── CMakeFiles
    ├── CTestTestfile.cmake
    ├── Makefile
    ├── Testing
    ├── _datasources
    ├── api_fastq_coversion_test
    ├── cli_fastq_coversion_test
    ├── cmake_install.cmake
    ├── data
    └── output

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (2d6439a) to head (0fb8d58).

Additional details and impacted files

@@            Coverage Diff            @@
##              main       #77   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            2         2           
  Lines           28        28           
=========================================
  Hits            28        28           

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