UI: enable folding of all cashflows for one year

[vectorien]

Allow folding of all cashflows for a year in tenants.html (using same js function as for folding all cashflows per tenant)

I think tis makes sense fpr a good UX, especially once there are severeal years of cashflows for a tenant

[oadam]

:+1:

[oadam]

Best option is to display 1 year per default and add a button at the bottom that loads all the rest