add py.typed marker to xivo-lib-python

Blocked until resulting type errors in dependent projects are fixed

For example, for wazo-amid:

Can confirm this will generate new mypy errors in projects which currently have xivo-lib-python included in the mypy environment(those projects which don’t explicit include xivo-lib-python in the additional_dependencies of the mypy linter will continue considering the library as missing).

Currently this include

• wazo-amid

• wazo-dird

• wazo-dird-client

• check impact on depend code bases(may break type checking if xivo-lib-python annotations were not used before)