Migrate to Rais 8.0

- Remove all Rodauth stuff and implement simple custom auth
- Migrate from sprockets to propshaft, hack some bootstrap stuff

app/controllers/sessions_controller.rb

@@ -0,0 +1,24 @@
+class SessionsController < ApplicationController
+  allow_unauthenticated_access only: %i[ new create ]
+  rate_limit to: 10, within: 3.minutes, only: :create, with: -> { redirect_to new_session_url, alert: "Try again later." }
+
+  def new
+    redirect_to :root if authenticated?
+  end
+
+  def create
+    redirect_to :root if authenticated?
+
+    if user = User.authenticate_by(params.permit(:email_address, :password))
+      start_new_session_for user
+      redirect_to after_authentication_url
+    else
+      redirect_to new_session_path, alert: "Try another email address or password."
+    end
+  end
+
+  def destroy
+    terminate_session
+    redirect_to new_session_path
+  end
+end