Fix & normalize Coop frontmatter YAML

Also ensure newline at EOF.

This was achieved by running the new normalize_coop_frontmatter.rb
script which basically reads in the frontmatter, parses it and dumps it
back out.

I had to manually fix some telephone numbers which had been incorrectly
parsed as some kind of number rather than as strings.

scripts/normalize_coops_frontmatter.rb

@@ -0,0 +1,12 @@
+require 'bundler/setup'
+require 'yaml'
+
+root_path = Pathname.new(__dir__).join('..')
+
+Dir[root_path.join('_coops/*.md')].each do |path|
+  content = File.read(path)
+  body = content.split("\n").reverse.take_while { |l| l != "---" }.reverse.join("\n")
+  metadata = YAML.safe_load(content)
+  frontmatter = YAML.dump(metadata)
+  File.write(path, frontmatter + "---" + "\n" + body)
+end