create api endpoint for showing planned upkeeps #49
add `closed` field to upkeep record #49
add correct aggregation function to the bool column #49
client code: upkeep has three params #49
add empty planned upkeeps page #49
Merge branch 'master' into i49

Conflicts:
	client/src/Crm/Component/Navigation.hs
	client/src/NoMain.hs
display table of planned upkeeps #49
add ascending ordering by date to fetch upkeeps #49
link to the company from planned upkeeps page #49