Update loader wizard table.read section

[SaOgaz]

Currently the top of the loader wizard looks like so...

We would like to entirely restructure the top section of the wizard that relates to the table.read command that happens on the backend. A few ideas have been proposed.

One approach would be some waterfalling drop down menus. The first level would be the format drop down (we could even generate this first drop down dynamically from the astropy table module itself), with further drop down menus based on additional parameter options.

Another approach, or one we could mix in with the above approach, would be to have an initial section/choice for format, and then a separate pop up window for more "advanced" table.read options. This could involve a mix of some common pre-set parameter options (drop downs, check boxes, single blank fields).

This was discussed at a few breakouts on the loader wizard (@kassin @nluetzge @hcferguson)