CMake Project Manager: Support presets functionality

cmake [<options>] -S <path-to-source> --preset=<preset-name>``
  Uses ``<path-to-source>`` as the source tree and reads a preset from
  ``<path-to-source>/CMakeSettings.json``. The preset specifies the generator
  and the build directory, and optionally a list of variables and other
  arguments to pass to CMake. The :manual:`CMake GUI <cmake-gui(1)>` can also
  recognize ``CMakeSettings.json`` files.

  The ``CMakeSettings.json`` file is a JSON document with an object as the
  root:

  .. code-block:: json

    {
      "configurations": [
        {
          "name": "Default Config",
          "generator": "Ninja",
          "buildRoot": "${projectDir}/build/default",
          "cmakeCommandArgs": "-DCMDLINE_ARGUMENT=ON",
          "variables": [
            {
              "name": "VARIABLE_ARGUMENT",
              "value": "OFF"
            }
          ]
        }
      ]
    }

  The root object recognizes the following fields:

  ``configurations``

    An array of preset objects. Each preset may contain the following fields:

    ``name``

      A required string representing the name of the preset.

    ``generator``

      A required string representing the generator to use for the preset.

    ``buildRoot``

      A required string representing the path to the output binary directory.
      This field supports variable expansion.

    ``cmakeCommandArgs``

      An optional string representing additional arguments to pass to CMake as
      if they had been passed from the command line. This field supports
      variable expansion.

    ``variables``

      An optional array of variable objects. Each variable must have the
      following fields:

      ``name``

        A required string representing the name, and optionally the type, of
        the variable. This may be specified as ``<name>`` or ``<name>:<type>``.

      ``value``

        A required string representing the value of the variable. This field
        supports variable expansion.

      Each object in ``variables`` is passed to CMake as ``-D<name>=<value>``.

  As mentioned above, some fields support variable expansion. This variable
  expansion is specific to ``CMakeSettings.json``, and is unrelated to CMake
  variables. Variables are recognized in the form ``${<variable-name>}``.
  It is an error to not put a closing brace at the end of a variable name. For
  example, ``${projectDir`` is invalid.

  Dollar signs (``$``) can be escaped using a backslash (``\``). Only dollar
  signs are escaped; any other backslash is preserved as-is. For example,
  ``\$`` will be interpreted as ``$``, ``\\$`` will be interpreted as
  ``\$``, and ``\a`` will be interpreted as ``\a``. However, note that since
  you are writing a JSON document, backslashes have to be double-escaped. For
  example, ``"\\$"`` will be interpreted as ``$``, ``"\\\\$"`` will be
  interpreted as ``\$``, and ``"\\a"`` will be interpreted as ``\a``.

  Recognized variable names include:

  ``projectFile``

    Path to the project's ``CMakeLists.txt`` file. Equivalent to
    ``${projectDir}/CMakeLists.txt``.

  ``projectDir``

    Path to the project directory.

  ``thisFile``

    Path to this ``CMakeSettings.json`` file. Equivalent to
    ``${projectDir}/CMakeSettings.json``.

  ``name``

    Name specified in the preset's ``name`` field.

  ``generator``

    Generator specified in the preset's ``generator`` field.