add functions to manage totest

first https://progress.opensuse.org/issues/2550
implement factory_snapshottable

issue https://progress.opensuse.org/issues/2552
implement generic function to manipulate prj flags

https://progress.opensuse.org/issues/2556
Merge pull request #146 from openSUSE/coolo_totest

for python reviewer joy
check the ISO sizes of the products

https://progress.opensuse.org/issues/2558
Merge pull request #147 from openSUSE/coolo_totest

check the ISO sizes of the products
remove debug output
also build disable 2nd ring staging
we need to make sure to write out only those problems we rebuild for or that are old
fix use of wrong hash
porting set_release.sh to a python function

Can't test atm as factory is not snapshottable
Merge pull request #148 from openSUSE/set_release

porting set_release.sh to a python function
implement some workflow for the totest manager

This needs a lot of testing and watching, but possibly we can add more checks
and more features in it

issue https://progress.opensuse.org/issues/2562
Merge pull request #149 from openSUSE/coolo_2562

implement some workflow for the totest manager
if there are no jobs, it's inprogress and not passed (due to lack of failures)
Release less, test more
avoid overwriting the release in totest while we publish the previous one
reindent
Merge pull request #150 from openSUSE/coolo_2584

Release less, test more
accept other new requests after accepting staging prjs