feat: add a common upload endpoint (#7806)

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

app/controllers/api/v1/upload_controller.rb

@@ -0,0 +1,13 @@
+class Api::V1::UploadController < Api::BaseController
+  def create
+    file_blob = ActiveStorage::Blob.create_and_upload!(
+      key: nil,
+      io: params[:attachment].tempfile,
+      filename: params[:attachment].original_filename,
+      content_type: params[:attachment].content_type
+    )
+    file_blob.save!
+
+    render json: { file_url: url_for(file_blob), blob_key: file_blob.key, blob_id: file_blob.id }
+  end
+end