Allocation-client subpage

[DO NOT MERGE] only for review
maybe we should use transaction here (for example commit_on_success) - what should happen when you delete all previous percents and then there will be an error during saving new percents? Some of the new percents will be saved, but they will not sum up to 100%. IMO we should either save all of them or non of them (and keep old percents) when something goes wrong.