Calculate Volunteer Numbers for 2021/22 for ACNC reporting

[mlandauer]

We do this once per year and we are at that time of year again.

Last year's numbers were calculated in #338

[mlandauer]

As per previous years we're adding up the number of unique people that made right to know requests and the number of code contributions in github.

This time we're getting the rtk requests data by using metabase. The final result is available at https://metabase.oaf.org.au/public/dashboard/23639e73-9dfc-439b-a2a7-b4632b9c8017 - it shows the last two financial years (so I could check that this number is right by comparing it to #338).

The github contributors (non planningalerts) for 2021/22:

bob
dependabot[bot]
mackaymackay
Mark
Mark Cottman-Fields
Matthew Landauer
Taz17
Tseyi Okorodudu
vagrant

That adds up to 3 once we remove bots and people that have been paid by OAF.

The planning alerts contributors for 2021/22:

Matthew Landauer
Taz17
tseyiokorodudu

That comes to 0 once remove people paid by OAF. Eek.

[mlandauer]

The total then for the 2021/22 year is 681 + 3 + 0 = 684