Allow to SignatureSheet parse new fields

- In the previous version, each signature was equivalent to a document
  and we separated them by commas.
  Now each signature may also need the fields birth date and postal code.
  So we separated each signature with a semicolon and separated each of
  its fields by commas.
  Example old version: "12345678X, 87654321Y"
  Example new version:
  "12345678X, 31/12/1980, 28001; 87654321Y, 31/12/1981, 28002"

- Update translations:
 "Write the numbers separated by commas (,)" to
 "Write the numbers separated by semicolons (;)"

spec/features/admin/signature_sheets_spec.rb

@@ -39,7 +39,7 @@ describe "Signature sheets" do
 
       select "Citizen proposal", from: "signature_sheet_signable_type"
       fill_in "signature_sheet_signable_id", with: proposal.id
-      fill_in "signature_sheet_required_fields_to_verify", with: "12345678Z, 1234567L, 99999999Z"
+      fill_in "signature_sheet_required_fields_to_verify", with: "12345678Z; 1234567L; 99999999Z"
       click_button "Create signature sheet"
 
       expect(page).to have_content "Signature sheet created successfully"
@@ -61,7 +61,7 @@ describe "Signature sheets" do
 
       select "Investment", from: "signature_sheet_signable_type"
       fill_in "signature_sheet_signable_id", with: investment.id
-      fill_in "signature_sheet_required_fields_to_verify", with: "12345678Z, 1234567L, 99999999Z"
+      fill_in "signature_sheet_required_fields_to_verify", with: "12345678Z; 1234567L; 99999999Z"
       click_button "Create signature sheet"
 
       expect(page).to have_content "Signature sheet created successfully"
@@ -89,14 +89,14 @@ describe "Signature sheets" do
     user = Administrator.first.user
     signature_sheet = create(:signature_sheet,
                              signable: proposal,
-                             required_fields_to_verify: "12345678Z, 123A, 123B",
+                             required_fields_to_verify: "12345678Z; 123A; 123B",
                              author: user)
     signature_sheet.verify_signatures
 
     visit admin_signature_sheet_path(signature_sheet)
 
     expect(page).to have_content "Citizen proposal #{proposal.id}"
-    expect(page).to have_content "12345678Z, 123A, 123B"
+    expect(page).to have_content "12345678Z; 123A; 123B"
     expect(page).to have_content signature_sheet.created_at.strftime("%B %d, %Y %H:%M")
     expect(page).to have_content user.name