docs/templates: put existing doc under 'Templates by App' section
docs/templates: put existing doc under 'Templates by App' section

This anticipates future sections.

twidi/satchmo,Ryati/satchmo,ringemup/satchmo,Ryati/satchmo,dokterbob/satchmo,dokterbob/satchmo,ringemup/satchmo,twidi/satchmo