Add feature flags, RS dashboard dummy

closes #124
refs #94

Gemfile.lock

@@ -133,6 +133,12 @@ GEM
     flipper-active_record (0.28.0)
       activerecord (>= 4.2, < 8)
       flipper (~> 0.28.0)
+    flipper-ui (0.28.0)
+      erubi (>= 1.0.0, < 2.0.0)
+      flipper (~> 0.28.0)
+      rack (>= 1.4, < 3)
+      rack-protection (>= 1.5.3, <= 4.0.0)
+      sanitize (< 7)
     fugit (1.7.2)
       et-orbi (~> 1, >= 1.2.7)
       raabro (~> 1.4)
@@ -204,6 +210,8 @@ GEM
     raabro (1.4.0)
     racc (1.6.0)
     rack (2.2.4)
+    rack-protection (3.0.6)
+      rack
     rack-test (2.0.2)
       rack (>= 1.3)
     rails (7.0.4)
@@ -288,6 +296,9 @@ GEM
     ruby2_keywords (0.0.5)
     rufus-scheduler (3.8.2)
       fugit (~> 1.1, >= 1.1.6)
+    sanitize (6.0.1)
+      crass (~> 1.0.2)
+      nokogiri (>= 1.12.0)
     sentry-rails (5.8.0)
       railties (>= 5.0)
       sentry-ruby (~> 5.8.0)
@@ -381,6 +392,7 @@ DEPENDENCIES
   faraday
   flipper
   flipper-active_record
+  flipper-ui
   importmap-rails
   jbuilder (~> 2.7)
   letter_opener