* bump_dependencies.md: add nim-results dependency
* change imports stew/results to results
* switching to Nim 2.0.8
* waku.nimble: reflect the requirement nim 1.6.0 to 2.0.8
Adding --mm:refc as nim 2.0 enables a new garbage collector that we're
not yet ready to support
* adapt waku code to Nim 2.0
* gcsafe adaptations because Nim 2.0 is more strict
* db_postgres: use prepared statements on most freq select queries
* db_postgres/dbconn.nim adding better feedback in case of query error
* dbconn: use of isOkOr
* pgasyncpool: refactor to reduce code (valueOr, catch:)
* db_postgres, postgres_driver: better performance by using callback.
There were a bunch of milliseconds being lost due to multiple-row
processing. This commit aims to have the minimum possible row
process time.
* pgasyncpool: clarifying logic around pool conn management.
* db_postgres: removing duplicate code and more searchable proc names.
It starts an asynchronous infinite task that checks the connectivity
with the database. In case of error, the postgres_healthcheck task
tries to reconnect for a while, and if it determines that the connection
cannot be resumed, then it invokes a callback indicating that
situation. For the case of the `wakunode2` app, this callback
quits the application itself and adds a log trace indicating
the connectivity issue with the database.
