move sentry::python to its own file
extract sentry::install to separate module file
move entry point to init.pp
allow for different install methods
move requiring sentry::python to its install method
allow specifying method
move File statement for requirements.txt into default install
fix the way we switch the install method
remove duplicate statement
remove duplicate file statement
update requirements to something that works for me

based on pip freeze after doing a fresh sentry install