bump app metrics packages to 4.1.0 preview

bump to latest app metrics stable version

updating to netcore3.1

bump to app metrics 4.0.0 preview, target netcoreapp3.0

remove health and net framework samples, bumping to app metrics 3.2

updating full framework health sample dependencies

updating net452 sample dependencies

updating aspnet core health sample dependencies

updating aspnet core sample dependencies

apply min weight resevoir to samples

updating full framework sample apps packages

updating asp.net core health sample packages

updating asp.net core sample packages

net452, net461 - updating app metrics health packages to 2.1.0 alpha

net452 - updating app metrics packages to 3.0.0 alpha