BaseCollector: Improving retrieve_uri method

Don't stop when a 404 error happens
Remove obsolete sorting stuff
Make "all expenses" code generic so it can be reused everywhere

This moves the table and the datatables javascript code into template tags, and
also factores out most of the query_all view into a separate helper function that
other query views will be able to use - it only takes a columns list of tuples
with column names and types.
Make supplier detail reuse the all expenses generic code
Make legislator detail reuse the all expenses generic code
per-legislator: sum expenses done by the same person on differnt mandates/parties

We may have several mandates for a legislator, potentially with different parties.
We only want to show one line per legislator, though, so sum the expenses and list
all parties in the party column.
Initial version of CMSP Collector
Per Legislator: Improving party column

Showing year_end only if there is one
Adjust search query for currency values so they are proper floating point numbers
Make /admin (without the trailing /) also get to the admin
Register Legislature on admin
detail-supplier: top-buyers: prefix link to detail-legislator with institution siglum