Remove bootstrap gems

We're not using them anymore, and they were injecting the old sass
processor sassc into our dependencies, causing errors.

Finally figured this out thanks to
orchidjs/tom-select#561 (comment)

Gemfile

@@ -53,9 +53,6 @@ gem 'sitemap_generator'
 
 # FRONTEND FRAMEWORKS ---------------------------------------------------------
 
-# Bootstrap CSS framework
-gem 'bootstrap', '~> 5.1'
-
 # Bootstrap forms
 gem 'bootstrap_form', '~> 5.0'
 

Gemfile.lock

@@ -79,20 +79,14 @@ GEM
       activerecord (>= 3.2, < 8.0)
       rake (>= 10.4, < 14.0)
     ast (2.4.2)
-    autoprefixer-rails (10.4.15.0)
-      execjs (~> 2)
     base64 (0.1.1)
     bcrypt (3.1.19)
     bibtex-ruby (6.0.0)
       latex-decode (~> 0.0)
     bindex (0.8.1)
-    bootstrap (5.3.1)
-      autoprefixer-rails (>= 9.1.0)
-      popper_js (>= 2.11.8, < 3)
-      sassc-rails (>= 2.0.0)
-    bootstrap_form (5.2.3)
-      actionpack (>= 6.0)
-      activemodel (>= 6.0)
+    bootstrap_form (5.3.2)
+      actionpack (>= 6.1)
+      activemodel (>= 6.1)
     breadcrumbs (0.3.0)
       actionview
       activesupport
@@ -273,7 +267,6 @@ GEM
     pg_search (2.3.6)
       activerecord (>= 5.2)
       activesupport (>= 5.2)
-    popper_js (2.11.8)
     postgres-copy (1.7.1)
       activerecord (>= 5.1)
       pg (>= 0.17)
@@ -381,14 +374,6 @@ GEM
       ffi (~> 1.12)
     ruby2_keywords (0.0.5)
     rubyzip (2.3.2)
-    sassc (2.4.0)
-      ffi (~> 1.9)
-    sassc-rails (2.1.2)
-      railties (>= 4.0.0)
-      sassc (>= 2.0)
-      sprockets (> 3.0)
-      sprockets-rails
-      tilt
     sax-machine (1.3.2)
     selenium-webdriver (4.12.0)
       rexml (~> 3.2, >= 3.2.5)
@@ -410,18 +395,10 @@ GEM
     spring-watcher-listen (2.1.0)
       listen (>= 2.7, < 4.0)
       spring (>= 4)
-    sprockets (3.7.2)
-      concurrent-ruby (~> 1.0)
-      rack (> 1, < 3)
-    sprockets-rails (3.4.2)
-      actionpack (>= 5.2)
-      activesupport (>= 5.2)
-      sprockets (>= 3.0.0)
     ssrf_filter (1.1.2)
     stimulus-rails (1.2.2)
       railties (>= 6.0.0)
     thor (1.2.2)
-    tilt (2.2.0)
     timeout (0.4.0)
     turbo-rails (1.4.0)
       actionpack (>= 6.0.0)
@@ -464,7 +441,6 @@ DEPENDENCIES
   activerecord-session_store
   annotate
   bibtex-ruby
-  bootstrap (~> 5.1)
   bootstrap_form (~> 5.0)
   breadcrumbs
   bullet