Py open sci review

* Update README.md

Fix typo (readme.md): l7 on package name

* Update README.md

Fix typo (readme.md): double spaces

* Update README.md

Edit (general): new line at each full stop in a markdown paragraph.

* Update contributing.rst

fix typo (contributing.rst): double spaces

* Update contributing.rst

Edit (general): adding a new line at each full stop in a rst paragraph.

* Update example workflow.rst

Edit (general): add a new line at each full stop in a markdown or rst paragraph.

* Update index.rst

Edit (general): add a new line at each full stop in a markdown or rst paragraph.

* wet_dry_drop() has become outside the normal workflow, what was being done in the try/except was a bit proactive and gets problematic with keeping the functions in a linear workflow.

* from harmonize -> clean: df_checks(). add_qa_flag()

* convert_unit_series() moved harmonize -> convert

* Import specific functions instead of module

* Fix docs examples

* Module needs to be imported for example

* 'Filter/sieve residue' & 'Yield' now included in this domain. This is meant to get the updated list, but will need to keep an eye out for additions for the example in docs like this. Especailly right now as there may be updates with WQX 2.0 -> 3.0.