On each plugin initialization we create a separate python interpreter
which gets stored in the plugin_ctx. The main interpreter is
stored in py_ctx and is used for creating more interpreters (if more plugins
get loaded) and final python deinitialization.
The "traceback" module import and the ImportBlocker initialization was
moved, because it has to happen inside the plugin specific interpreters.
Separate sudo io plugin symbols are created which stores wrapper
functions adding the context of which python plugin the callback is
about.
These sudo io plugin "slots" get generated with macros by the preprocessor.
This makes sudo support loading multiple python IO plugins like this:
(note the differences in the symbol names)
Plugin python_io python_plugin.so ModulePath=... ClassName=SudoIOPlugin1
Plugin python_io1 python_plugin.so ModulePath=... ClassName=SudoIOPlugin2
Plugin python_io2 python_plugin.so ModulePath=... ClassName=SudoIOPlugin3
IO/Group/Policy Python API version is displayed instead of sudo version,
because that is not very meaningful in this context.
They are only displayed in verbose mode.
Example plugins express it more concrete that they are displaying their
version, not the API version.
