-Slightly more detail on the `Thermodynamics` landing page.
-A few small typo fixes
- Correcting inconsistencies in the `Species` page with when the `hat`
over molar property variables
was used.
- Replaced the number 0 with `^\circ` to indicate reference properties.

Moves transport property information from the `species` and `phases`
pages to the `Transport` landing page. The information on the
`Transport` landing page is still insufficient (imho), but as
the current changes fully reproduce the information currently on the
website, I will address this in a future PR.

Update pages/science/thermodynamics.rst

Explaining the ideal gas law.
- Fix math formatting.
- Link to info on Maxwell relations.

Update pages/science/species-thermo.rst
- Grammar
- Fix math formatting.

Typo fix on pages/science/transport.rst