chunker: Increase default max record size so hunker does not fail to store big records
reduce max failures per task setting to a practical value of 3
add builder recipe
enable disco proxy by default
remove dot hack (partly revert 444b670)

was silently breaking when using url containing dots as DISCO_PROXY
increase GC_PROGRESS_INTERVAL to 3 hours
Added recursivity to the chown
increase save timeout

in order to allow storing very large files