Update CMake and add CI

The CMake options have been prefixed with DEDISP_, the options are now: DEDISP_BUILD_BENCHMARKS, DEDISP_ENABLE_DEBUG and DEDISP_BUILD_TESTS). Also, the variables were used incorrectly, without ${}. When DEDISP_BUILD_TESTS is enabled, CMake's testing is now also enabled and the test binaries are registered with CTest.

These were all prerequisites to add CI that does linting (using pre-commit), build the code, executes the benchmarks, executes the tests.

There was some INSTALL file that was of no use any more and was therefore removed.