Refactors User#calculate rec_life_insurance again to remove arbitrary assignment
Adds redirect to ApplicationController#log_in
Adds flash and redirect to ApplicationController#log_out
Consolidates log_in function and flash message
Fixes infinite redirect loop because of params being strings
Removes flash and redirect from SessionsController#destroy because included in log_out
Requires owner to see a user's page, and redirects to the current user's page