chore(archive): allow request concurrency towards PostgreSQL

[jm-clius]

In order to allow for a scalable and fault-resistant Waku Archive technology as set out in waku-org/pm#12, we have decided to implement a PostgreSQL backend.

Work on adding basic support for PostgreSQL has started: #1590

A related work item, required for scalability, is to allow processing store requests concurrently. The standard library integration will, similar to the previous SQLite-based implementation, block on processing a store query, which is not scalable at high store query rates.

A simple solution may be to adapt https://github.com/treeform/pg to work with nim-chronos, i.e. an async wrapper functioning as an extension of the std library API.

cc @cammellos @LNSD

Tasks

• Allow to put and retrieve messages from PostgreSQL database.
• Make sure the interaction with the PostgreSQL is asynchronous.
• Implement the whole "waku archive" through the postgresql driver.
• Add the config option to allow wakunode2 interact with postgres database instead of sqlite.
• [ ] Keep the sql queries in external .sql plain text files ( comment ) . Also, important to pay attention to the @LNSD comment: Add postgres basic support #1590 (comment) -> created a separate issue
• [ ] Optimize the database. We need a rapid response when duplicate msgs happens. -> created a separate issue
• Run the current sqlite unittest set for the postgresql driver.
• [ ] Apply @Menduist 's enhancement suggestions for a more appropriate asynchronous handling: feat(common): added postgress async pool wrapper #1631 (comment) -> created a separate issue
• [ ] Protect the nwaku compilation process so that the user has the libpq library properly installed. -> created a separate issue
• [ ] Create a docker file to bring nwaku + PostgreSQL simultaneously. Ping @LordGhostX when completed. -> created a separate issue

[Ivansete-status]

This is Done.