Equations without numbers and eqref

[tlienart]

See discussion here: https://discourse.julialang.org/t/how-to-suppress-equation-numbers-in-franklin/73835/4

Possible actions:

• define explicitly \begin{align*} and \begin{equation*} and \begin{eqnarray*} and make them do the trick explained in the discussion
• possibly define $$* ... $$ as a custom environment (maybe in Xranklin)
• remove the docs with suppressing numbers as it will lead to erroneous references