webos: Move requires and most definitions to .inc file

* allows to reuse webos.inc by other distributions
* this is first part of bigger DISTRO conf cleanup

[GF-2417] Reorganize distro configs

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@palm.com>
Change-Id: I06eba72b1d1f97d676217bdcd14db3e3311d167c
Reviewed-on: https://g2g.palm.com/1590
Reviewed-by: Martin Jansa <martin.jansa@palm.com>
Tested-by: Martin Jansa <martin.jansa@palm.com>
Reviewed-by: Keith Derrick <keith.derrick@lge.com>
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>
webos: Move DISTRO_FEATURES to separate .inc

* doesn't look very useful now, but later we'll limit DISTRO_FEATURES
  and DISTRO_FEATURES_LIBC
* this is part of bigger DISTRO conf cleanup

[GF-2417] Reorganize distro configs

Open-webOS-DCO-1.0-Signed-off-by: Martin Jansa <martin.jansa@palm.com>
Change-Id: Ia48df832a1dcf383ebe9f660d186d6bf45f47ebe
Reviewed-on: https://g2g.palm.com/1591
Reviewed-by: Martin Jansa <martin.jansa@palm.com>
Tested-by: Martin Jansa <martin.jansa@palm.com>
Reviewed-by: Herb Kuta <herb.kuta@lge.com>
Reviewed-by: Susan Montooth <susan.montooth@lge.com>