Move nanoc.rake to the toplevel rake/tasks/ dir

Rakefile.rb

@@ -1,6 +1,6 @@
 require "bundler/setup"
 
-load "twenty-client/tasks/nanoc.rake"
+load "rake/tasks/nanoc.rake"
 load "rake/tasks/gem.rake"
 load "rake/tasks/rubocop.rake"
 load "rake/tasks/server.rake"

rake/tasks/nanoc.rake

@@ -1,6 +1,6 @@
 namespace :nanoc do
   require "bundler/setup"
-  workdir = File.realpath File.join(__dir__, "..")
+  workdir = File.realpath File.join(__dir__, "..", "..", "twenty-client")
 
   desc "Clean the build/ directory"
   task :clean do

twenty-client/Rakefile.rb

@@ -1,5 +1,4 @@
 require "bundler/setup"
-load 'tasks/nanoc.rake'
 namespace :schema do
   desc "Generate src/js/types/schema.ts"
   task :regen do