Make dynamic loading protocol for controller MishkaSocial

[shahryarjb]

This part of code has no plugin in the project, hence it should be selectable completely. create a way to load every plugin like this in MishkaInstaller.

link: https://github.com/mishka-group/mishka-cms/blob/40c3dfaf013a9f2e3b26244d0dc9d251f1236607/apps/mishka_html/lib/mishka_html_web/controllers/auth_controller.ex#L409-L419