Mimir single binary should "just work" with the default config

[pracucci]

Mimir single binary should "just work" with the default config. Ideally, a single test replica of Mimir should run locally with no custom config but that's probably too much: stretching this a bit, we should require as least as config as possible to start it up.

• Run compactor in single binary (-target=all) and change compactor default config to split-and-merge compaction strategy #814
• Change default blocks_storage.backend to filesystem #831
• Set a default filesystem directory for blocks storage #832
• Remove ability to start components without sharding #856
• Remove sharding strategy options #857
• Test with as small a config is possible to make sure this is reasonable #1024

[simonswine]

There was some comment in this issue about that: https://github.com/grafana/mimir-squad/issues/391#issuecomment-982551712:

Change default blocks_storage.backend to filesystem

This seems like a very strange default value, with limited use.

But perhaps better than failing with s3 being the default.

This was my thinking behind it that for all other blocks_storage.backends, you are required to set at least a bucket name or some form of authentication, while we could filesystem without further consideration.

I guess it can go horribly wrong if the filesystem is used with multiple instances and the folder is not shared by them.

[pracucci]

I think all work has been done here. I'm going to close this issue. Please reopen and comment with details if anything has been left out.