Refactored static build process to use static-build/CMakeLists.txt
instead of Dockerfile.staticbuild (this allows to support static
build on macOS). Following third-party dependencies for static build
are installed via cmake `ExternalProject_Add`:
  - OpenSSL
  - Zlib
  - Ncurses
  - Readline
  - Unwind
  - ICU

* Added support static build for macOS
* Fixed `CONFIGURE_COMMAND` while building bundled libcurl for static
  build at file cmake/BuildLibCURL.cmake:
    - disable building shared libcurl libraries (by setting
      `--disable-shared` option)
    - disable hiding libcurl symbols (by setting
      `--disable-symbol-hiding` option)
    - prevent linking libcurl with system libz (by setting
      `--with-zlib=${FOUND_ZLIB_ROOT_DIR}` option)
* Removed Dockerfile.staticbuild
* Added new gitlab.ci jobs to test new style static build:
  - static_build_cmake_linux
  - static_build_cmake_osx_15
* Removed static_docker_build gitlab.ci job

Closes #5095

Co-authored-by: Yaroslav Dynnikov <yaroslav.dynnikov@gmail.com>