Issue1161 version

[Didou09]

Main changes:

• Following strategy from
• tofu/_version.py created, where version is single-sourced
• meson.build reads that
• pyproject.toml has dynamic version from meson

Only remaining redundancy is the git tag, which may be addressed later by testing git repo from inside tofu/_version.py

Issues:

Fixes, in devel, issue #1161