repo clone folder layout rework

repo clone folder layout rework

As discussed during the F2F in Spain, we will tidy up the folder structure
of the cloned repositories a bit.

Above is a first version. Please review.

|-- bsp
|   |-- meta-altera
|   |-- meta-boundary
|   |-- meta-freescale
|   |-- meta-intel
|   |-- meta-qcom
|   |-- meta-raspberrypi
|   |-- meta-rcar
|   |-- meta-renesas-rcar-gen3
|   |-- meta-rtlwifi
|   |-- meta-sancloud
|   |-- meta-synopsys
|   `-- meta-ti
|-- external
|   |-- meta-gplv2
|   |-- meta-openembedded
|   |-- meta-qt5
|   |-- meta-sdl
|   |-- meta-security
|   |-- meta-spdxscanner
|   |-- meta-updater
|   |-- meta-updater-qemux86-64
|   |-- meta-virtualization
|   `-- poky
|-- meta-agl
|-- meta-agl-devel
|-- meta-agl-extra
|-- meta-agl-demo
|-- meta-agl-cluster-demo
`-- meta-agl-telematics-demo

Bug-AGL: SPEC-2450

Change-Id: Ia10d0cba1f390770bbb0cf345b5ae389a28b30c8
Signed-off-by: Jan-Simon Möller <jsmoeller@linuxfoundation.org>