Create Docs for deb and rpm repositories

[petethepig]

Currently we distribute pyroscope rpm and deb packages but we don't have repositories set up.

TODO

• [x] set up rpm repos
• [x] set up deb repos
• [x] update release script to update the repos
• [x] put old packages in these repos
• [ ] update docs to reflect the changes

[eh-am]

They are all here https://pyroscope.io/downloads/