Handle corrupt git clones

When cloning the git repo:
1. Try to clone
2. If there's already a build directory reset it
3. Check the clone is valid

If anything goes wrong during that process:
1. Delete the clone directory
2. Clone it again
3. Check the clone is valid

Raise any errors after that

lib/kamal/cli/build.rb

@@ -23,7 +23,9 @@ class Kamal::Cli::Build < Kamal::Cli::Base
         say "Building from a local git clone, so ignoring these uncommitted changes:\n #{uncommitted_changes}", :yellow
       end
 
-      prepare_clone
+      run_locally do
+        Clone.new(self).prepare
+      end
     elsif uncommitted_changes.present?
       say "Building with uncommitted changes:\n #{uncommitted_changes}", :yellow
     end
@@ -126,23 +128,4 @@ class Kamal::Cli::Build < Kamal::Cli::Base
         end
       end
     end
-
-    def prepare_clone
-      run_locally do
-        begin
-          info "Cloning repo into build directory `#{KAMAL.config.builder.build_directory}`..."
-
-          execute *KAMAL.builder.create_clone_directory
-          execute *KAMAL.builder.clone
-        rescue SSHKit::Command::Failed => e
-          if e.message =~ /already exists and is not an empty directory/
-            info "Resetting local clone as `#{KAMAL.config.builder.build_directory}` already exists..."
-
-            KAMAL.builder.clone_reset_steps.each { |step| execute *step }
-          else
-            raise
-          end
-        end
-      end
-    end
 end