add alias for booth

Booth can be replaced with any alias by replacing it in alias.en.yml. This change is introduced as some events do not use booth but uses other words such as stand.

app/views/conferences/_booths.haml

@@ -1,6 +1,6 @@
 .row
   .col-md-12
-    %h3.text-center Booths
+    %h3.text-center "#{(t'booth').pluralize.capitalize }"
 .row.row-centered
   - booths.each do |booth|
     .col-md-2.col-sm-2.col-centered.col-top.booth

app/views/conferences/_call_for_booths.haml

@@ -1,12 +1,12 @@
 - cache [conference_id, call, '#splash#callforbooths'] do
   .col-md-4.col-sm-4.text-center
     %h2
-      Call for Booths
+      Call for #{(t'booth').pluralize.capitalize }
     %p.lead
-      We are now accepting custom booth requests!
+      We are now accepting custom #{t'booth'} requests!
     %p
-      Would you like to request a new booth?
-      The submission period for booth requests is open
+      Would you like to request a new #{t'booth'}?
+      The submission period for #{t'booth'} requests is open
       %em
         = date_string(call.start_date, call.end_date) + '.'
       %b
@@ -14,6 +14,6 @@
         = pluralize(call.remaining_days, 'day')
         left!
     %p.cta-button
-      = link_to("Submit your request for booth",
+      = link_to("Submit your request for #{t'booth'}",
         new_conference_booth_path(conference_id),
         class: 'btn btn-success btn-lg text-center')

app/views/conferences/_conference_details.html.haml

@@ -44,9 +44,9 @@
               - if conference.program.cfp_open?
                 = link_to "Submit Proposal", new_conference_program_proposal_path(conference.short_title), class: 'btn btn-default'
             - if current_user && current_user.booths.where(conference_id: conference.id).count > 0
-              = link_to 'My Booth Requests', conference_booths_path(conference.short_title), class: 'btn btn-default'
+              = link_to "My #{(t'booth').capitalize } Requests", conference_booths_path(conference.short_title), class: 'btn btn-default'
             - elsif can? :new, conference.booths.new
-              = link_to 'Request Booth', new_conference_booth_path(conference.short_title), class: 'btn btn-default'
+              = link_to "Request #{(t'booth').capitalize }", new_conference_booth_path(conference.short_title), class: 'btn btn-default'
             - if current_user.nil? || !current_user.subscribed?(conference)
               = link_to 'Subscribe', conference_subscriptions_path(conference.short_title), method: :post, class: 'btn btn-default'
             - else