webos-image: db8=117

:Release Notes:
Restore _version, clean up start scripts and disk space checking

:Detailed Notes:
submissions/115..submissions/117
5d4a104 Update disk space information
6d582af Delete and re-create media db if corrupted
d2b7f7c Add space check for tempdb/mediadb
914c2c9 Clean up db8 upstart scripts
4d01a5c Restore version file when it is crashed

:Testing Performed:
MiniBAT GF-57515

:QA Notes:

:Issues Addressed:
[GF-57515] CCC: db8=117
[GF-56049] Restore '_version' file when it crashed
[GF-55278] workload distribution to improve input responsiveness during boot
[GF-53321] Provide mechanism to track DB usage on-device
[GF-53734] DB8 needs to force a factory reset if it has run out of space
[GF-57390] If media db corrupted, delete and re-create media db directory

Open-webOS-DCO-1.0-Signed-off-by: Oleksii Uratkin <oleksii.uratkin@lge.com>

Change-Id: Ib4ed5d2fe89cdb1f40958915d111a335874e525a
Reviewed-on: https://g2g.palm.com/4325
Reviewed-by: DCO Verification
Build: Oleksii Uratkin <oleksii.uratkin@lge.com>
Reviewed-by: Martin Jansa <Martin.Jansa@lge.com>
Reviewed-by: Build Verification
Reviewed-by: Joungyong Choi <joungyong.choi@lge.com>
Tested-by: Joungyong Choi <joungyong.choi@lge.com>