Introduce TI DRA7 vayu and cleanup template files

This changeset introduces the TI 'vayu' board.
We need to adapt the provided bsp layer 'meta-ti' as
it is only at YP 1.8 fido right now.
Two changes are needed/known:
a) BBMASK eudev bbappend (local.conf.sample)
b) apply patch for gcc5 to u-boot-ti-staging

On top thie changeset also does janitorial work on the templates:
- conf-notes is now in a folder common and symlinked
- layer additions have been sync'ed
- file layout sync'ed with templates in meta-agl-demo

Change-Id: Ib52a9252800d54d5105ac1f5354ad3a3b014188f
Signed-off-by: Jan-Simon Möller <jsmoeller@linuxfoundation.org>