Include either in synphot or in the docs a way to access all the tynt-generated filters

[eteq]

As a follow-on to #257, I'm realizing that I think none of the tynt-generated filters are actually present here. Should we provide either a snippet in the docs, or a copy of the tynt filter table for all the zillions of useful filters that tynt provides? Or do you think it is out-of-scope to do that in synphot @pllim ?

Motivation: I was pointing someone to synphot and they were like "where are the actual filters I need? Oh, look at all the stuff tynt has! I'll just use that." (for a use case where the approximations of the fft approach are definitely fine)

[pllim]

I think I actually shipped a subset of the parameters but as test data at:

synphot_refactor/setup.cfg

Line 64 in 2a382d7

synphot.filter_parameterization.tests = data/*

Supporting this officially as package data might get... political. This is because currently, all the throughputs are vetted by RedCat team. I do not want to ship a set of parameters but have no support in keeping them up-to-date. We need to have infrastructure in place to make sure the values will stay current and blessed by the respective instrument teams.