Add and apply rubocop rules for empty lines

We were very inconsistent regarding these rules.

Personally I prefer no empty lines around blocks, clases, etc... as
recommended by the Ruby style guide [1], and they're the default values
in rubocop, so those are the settings I'm applying.

The exception is the `private` access modifier, since we were leaving
empty lines around it most of the time. That's the default rubocop rule
as well. Personally I don't have a strong preference about this one.


[1] https://rubystyle.guide/#empty-lines-around-bodies

db/dev_seeds/polls.rb

@@ -2,7 +2,6 @@ require_dependency "poll/answer"
 require_dependency "poll/question/answer"
 
 section "Creating polls" do
-
   Poll.create!(name: I18n.t("seeds.polls.current_poll"),
                slug: I18n.t("seeds.polls.current_poll").parameterize,
                starts_at: 7.days.ago,
@@ -44,7 +43,6 @@ section "Creating polls" do
     end
     poll.save!
   end
-
 end
 
 section "Creating Poll Questions & Answers" do
@@ -121,7 +119,6 @@ section "Commenting Polls" do
 end
 
 section "Creating Poll Voters" do
-
   def vote_poll_on_booth(user, poll)
     officer = Poll::Officer.all.sample
 

db/dev_seeds/widgets.rb

@@ -1,5 +1,4 @@
 section "Creating header and cards for the homepage" do
-
   def create_image_attachment(type)
     {
       cached_attachment: Rails.root.join("db/dev_seeds/images/#{type}_background.jpg"),