add transaction activity analysis

[brenzi]

Like Fig 6 in https://encointer.org/charting-the-development-of-encointers-longest-established-community-currency/
Provide a plot and CSV with all the relevant raw and calculated data in the "internal" space

• store a list of voucher,governance accounts (in addition to acceptance points) to categorize

this plot should be public

[pifragile]

@brenzi, can you send a list of gevernance and voucher accounts?

[brenzi]

I think the excel has a list with all known accounts