* Ingest stacktraces in the new symdb

* Setup read in memory read path

* Fix up a comment placement

* Start setting up the read path

* Update to uint32

* Introduce stacktrace partition (#775)

* Introduce stacktrace partition

This determines the partition of a particular profile, by looking first
at its metadata:

* If there is a `Filename` on the main mapping use its
  filepath.Base(Filename)
* Failing that take the externally supplied `service_name`
* Fallback to `unknown`

Take the underlying string value and hash.

* After a chat with cyril we decided to not longer mod and use the hash
straight away.

We don't wanted to risk the collisions of two very big stacktrace
applications.

* Remove reconstructMeta from singleBlockQuerier

* support multiple versions of stacktraces resolver

* Integrate v2 reader for stacktraces in block reader

* Fixes tests

* Rewrite locations Ids

* Rewrite test for counting uniq stacktraces

* lint and fmt

* Fixes more tests

* Fixes leftover from todo

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Co-authored-by: Christian Simon <simon@swine.de>