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

spec/models/user_spec.rb

@@ -1,7 +1,6 @@
 require "rails_helper"
 
 describe User do
-
   describe "#headings_voted_within_group" do
     it "returns the headings voted by a user" do
       budget = create(:budget)
@@ -341,9 +340,7 @@ describe User do
   end
 
   describe "official_position_badge" do
-
     describe "Users of level 1" do
-
       it "displays the badge if set in preferences" do
         user = create(:user, official_level: 1, official_position_badge: true)
 
@@ -355,11 +352,9 @@ describe User do
 
         expect(user.display_official_position_badge?).to eq false
       end
-
     end
 
     describe "Users higher than level 1" do
-
       it "displays the badge regardless of preferences" do
         user1 = create(:user, official_level: 2, official_position_badge: false)
         user2 = create(:user, official_level: 3, official_position_badge: false)
@@ -371,15 +366,11 @@ describe User do
         expect(user3.display_official_position_badge?).to eq true
         expect(user4.display_official_position_badge?).to eq true
       end
-
     end
-
   end
 
   describe "scopes" do
-
     describe "active" do
-
       it "returns users that have not been erased" do
         user1 = create(:user, erased_at: nil)
         user2 = create(:user, erased_at: nil)
@@ -398,11 +389,9 @@ describe User do
         expect(User.active).to match_array [user1, user2]
         expect(User.active).not_to include(user3)
       end
-
     end
 
     describe "erased" do
-
       it "returns users that have been erased" do
         user1 = create(:user, erased_at: Time.current)
         user2 = create(:user, erased_at: Time.current)
@@ -411,7 +400,6 @@ describe User do
         expect(User.erased).to match_array [user1, user2]
         expect(User.erased).not_to include(user3)
       end
-
     end
   end
 
@@ -473,7 +461,6 @@ describe User do
       user.valid?
       expect(user.document_number).to eq("12345678B")
     end
-
   end
 
   describe "#erase" do
@@ -528,7 +515,6 @@ describe User do
 
       expect(Identity.exists?(identity.id)).not_to be
     end
-
   end
 
   describe "#take_votes_from" do
@@ -658,7 +644,6 @@ describe User do
       expect(user_2.reload.former_users_data_log).to include("id: #{user_1.id}")
       expect(user_1.reload.document_number).to be_blank
     end
-
   end
 
   describe "email_required?" do
@@ -710,7 +695,6 @@ describe User do
 
       expect(user.interests).to eq ["Sport"]
     end
-
   end
 
   describe ".find_by_manager_login" do
@@ -725,5 +709,4 @@ describe User do
       expect(User.find_by_manager_login("admin_user_#{user.id}")).to eq user
     end
   end
-
 end