DEV: Rename secure_media to secure_uploads (#18376)

This commit renames all secure_media related settings to secure_uploads_* along with the associated functionality.

This is being done because "media" does not really cover it, we aren't just doing this for images and videos etc. but for all uploads in the site.

Additionally, in future we want to secure more types of uploads, and enable a kind of "mixed mode" where some uploads are secure and some are not, so keeping media in the name is just confusing.

This also keeps compatibility with the `secure-media-uploads` path, and changes new
secure URLs to be `secure-uploads`.

Deprecated settings:

* secure_media -> secure_uploads
* secure_media_allow_embed_images_in_emails -> secure_uploads_allow_embed_images_in_emails
* secure_media_max_email_embed_image_size_kb -> secure_uploads_max_email_embed_image_size_kb

spec/tasks/uploads_spec.rb

@@ -52,9 +52,9 @@ RSpec.describe "tasks/uploads" do
         uploads.each { |upload| stub_upload(upload) }
       end
 
-      context "when secure media is enabled" do
+      context "when secure upload is enabled" do
         before do
-          SiteSetting.secure_media = true
+          SiteSetting.secure_uploads = true
         end
 
         it "sets an access_control_post for each post upload, using the first linked post in the case of multiple links" do
@@ -155,10 +155,10 @@ RSpec.describe "tasks/uploads" do
     end
   end
 
-  describe "uploads:disable_secure_media" do
+  describe "uploads:disable_secure_uploads" do
     def invoke_task
       capture_stdout do
-        Rake::Task['uploads:disable_secure_media'].invoke
+        Rake::Task['uploads:disable_secure_uploads'].invoke
       end
     end
 
@@ -166,7 +166,7 @@ RSpec.describe "tasks/uploads" do
       setup_s3
       uploads.each { |upload| stub_upload(upload) }
 
-      SiteSetting.secure_media = true
+      SiteSetting.secure_uploads = true
       UploadReference.create(target: post1, upload: upload1)
       UploadReference.create(target: post1, upload: upload2)
       UploadReference.create(target: post2, upload: upload3)
@@ -186,9 +186,9 @@ RSpec.describe "tasks/uploads" do
     let(:upload4) { Fabricate(:upload_s3, secure: true, access_control_post: post2) }
     let(:upload5) { Fabricate(:upload_s3, secure: false) }
 
-    it "disables the secure media setting" do
+    it "disables the secure upload setting" do
       invoke_task
-      expect(SiteSetting.secure_media).to eq(false)
+      expect(SiteSetting.secure_uploads).to eq(false)
     end
 
     it "updates all secure uploads to secure: false" do