Improve pie chart for Velocity versions

[Andre601]

Right now does bStats display each version individually for a velocity proxy. This will cause... extremely full pie charts due to each new git revision being counted as their own version:

I suggest to change this by having this be a drilldown pie with 3.3.0-SNAPSHOT (or similar version patterns) being the major version and every git revision being part of it.

[MiniDigger]

this would need to be done in velocity, not bstats
bstats already supports drill down charts, we just need to convert that one to a drill down and supply the data in the right format

i.e. this is what I did for papers legacy plugins chart: https://github.com/PaperMC/Paper/blob/9e171ef8ff0a0ec57ebc75772fc9de578c987059/patches/server/0012-Paper-Metrics.patch#L663-L694