Allow Push api to modify pprof sample values

[korniltsev]

Consider a pprof profile obtained with curl from

http://localhost:7240/debug/pprof/heap?seconds=239

This endpoint does the delta for both alloc_* and inuse* values, however most of the time we don't want to do this for inuse* values. Therefore we should not ingest this delta'd inuse* values.

Similar with regular (non delta'd) heap profile. Most of the time users want to ingest inuse* values and not alloc* values, because they are cumulative.

Someone may say this is a runtime bug/issue [1] [2] .

It is now impossible to ingest only delta'd alloc* values or only non delta'd inuse* values into pyroscope.

I propose we implement a push api parameter allowing to scale pprof sample values.

For example if we pass [1, 1, 0, 0] for delta'd profile, then we ingest only alloc values and zero-out inuse values
For another example if we pass [0, 0, 1, 1] for non delta'd profile, then we ingest only alloc

Similar to what runtime is already doing but with a more granularity. Here's another example. And my another draft for alloy which does this clientside before pushing to pyroscope