Merge grafana/phlare repo into grafana/pyroscope

[simonswine]

Problem

End-Users, contributors and developers face a fair bit of confusion with the two projects and especially the wording of the Phlare README is misleading

Goals

• Keep commit history intact
• Ensure commit messages that reference to issues and PRs stay correct (Avoid that Segment Tree bug fixes #123 in a message from grafana/phlare will link to a different PR in the grafana/pyroscope repo)
• Do not loose the stars
• Be able to release OG and Pyroscope weeklies

The Plan

Phase 1

• Script to do the merge of the repos: Add repo merge script phlare#808

Phase 2: Move repo atomically

• Run the script on 2023-07-18 13:00 UTC, ensure PRs no longer can be merged into grafana/phlare, make Grafana Pyroscope available in the next branch, switch default branch to next.

### Phase 3
- [x] Improve README.md in both projects.
- [ ] https://github.com/grafana/pyroscope/issues/2000
- [x] Rename phlare binaries to pyroscope https://github.com/grafana/pyroscope/pull/2023
- [ ] https://github.com/grafana/pyroscope/issues/2149
- [ ] @petethepig  Clean up the `og/` folder, decide what to keep what to remove and what to move out.
- [ ] Determine the future of the `pyroscope` subcommands. (currently phlare only supports `pyroscope server`)
- [ ] https://github.com/grafana/pyroscope/issues/2151
- [x] Ensure the `make generate` works again @cyriltovena https://github.com/grafana/pyroscope/pull/2140
- [x] Fix weekly builds @simonswine
- [ ] tag api/ and ebpf/ folder
- [ ] Merge and/or rename helm chart for pyroscope and phlare
- [x] [Update MAINTAINERS.md](https://github.com/grafana/pyroscope/pull/2155)

### Phase 4
* [ ] [Update examples](https://github.com/grafana/pyroscope/issues/2188)
* [ ]  The `og/` folder has disappeared
* [ ] No code imports of github.com/pyroscope-io/pyroscope anmymore
* [ ] First release of Grafana Pyroscope

[petethepig]

Little update from me, I deleted some things from /og directory, and started figuring out what to do with go packages (I will move some that we use and delete the rest). Here's the graph of dependencies: