Remove auto-fill of membership benefits

[maneesha]

Right now, membership benefits (number of workshops and number of instructor training seats) gets automatically filled in based on membership level. Because these benefits will change and may get customized, we would like to remove this feature and have these fields manually entered in.

[pbanaszkiewicz]

This should be fairly simple, as the required data to be entered is stored in amy/static/membership_create.js. I just want to make sure @maneesha this feature will not be needed again in future?

[maneesha]

Tagging @elletjies and @ErinBecker to confirm -- they recommended removing this feature entirely.