12/WAKU2-STORE: Production recommendations

[jm-clius]

Background

In practice, deploying a node running 13/WAKU2-STORE poses a number of production challenges. Although these could be addressed ad-hoc by different client implementations, a minimal feature set should be recommended in an RFC.

Specifically, the issues to address:

1. Guidance on how to dimension a store (both in terms of memory and persistent storage) to address issues such as: https://github.com/status-im/nim-waku/issues/702
2. Recommended settings to control the number of days a message can be stored as well as controlling the memory usage of a node.

Also see: https://github.com/vacp2p/rfc/issues/441 which affects dimensioning.