Homepage updater fixes

I have removed one of the homepage_* tables, split the update query by statements and integrated sentry (ref. #1598, #1601, #1549).

EDIT: I have removed also the other two homepage_* tables. Instead giving and receiving on participants are used. These fields are updated with triggers on tips table. Triggers on update of participants are still missing.

EDIT: Do not run it yet on a production size db. The calculation of giving and receiving for everyone takes forever. Need to look into it more.