[HG-174] Installer fails when doing upgrade due to existent table
[HG-177] Allow for single process export

This is a complete downgrade to the export process, sacrifice memory and time performance
just to avoid connections locks on Redis cache and session storage. Not adviced to use except
when the store contain few SKUs.

Exceptions messages could be:
    'failed to receive data from locale xx_XX'
    'protocol error, got '^^' as reply type byte'

Reseting cache connection per thread execution did not make any effect as well as disabling cache.
[HG-196] Show parent if product is selected as not visible

Simple products selected as not visible individually can not be accessed, 404 error.
Merge branch 'HG-196' into development
Merge branch 'HG-177' into development