CMake Interaction Update

Closes #6 (closed) , #8 (closed) .

• Allow the user to specify the Python interpreter to be used by the pystencils-sfg CMake module via a hint variable to the find module
• Allow the user to pass custom command line arguments to generator scripts through CMake
• Move the default output path for generated files to ${CMAKE_CURRENT_BINARY_DIR}/_gen/<target>/gen
• Allow the user to customize the output directory

docs/source/usage/project_integration.md

@@ -117,7 +117,7 @@ with the following signature:
 ```CMake
 pystencilssfg_generate_target_sources( <target> 
     SCRIPTS script1.py [script2.py ...]
-    [ARGS arg1 [arg2 ...]]
+    [SCRIPT_ARGS arg1 [arg2 ...]]
     [DEPENDS dependency1.py [dependency2.py...]]
     [FILE_EXTENSIONS <header-extension> <impl-extension>]
     [OUTPUT_MODE <standalone|inline|header-only>]
@@ -132,7 +132,7 @@ Any changes in the generator scripts, or any listed dependency, will trigger reg
 The function takes the following options:
 
  - `SCRIPTS`: A list of generator scripts
- - `ARGS`: A list of custom command line arguments passed to the generator scripts; see [](#custom_cli_args)
+ - `SCRIPT_ARGS`: A list of custom command line arguments passed to the generator scripts; see [](#custom_cli_args)
  - `DEPENDS`: A list of dependencies for the generator scripts
  - `FILE_EXTENSION`: The desired extensions for the generated files
  - `OUTPUT_MODE`: Sets the output mode of the code generator; see {any}`SfgConfig.output_mode`.