feature: enable veraison stores frontend for postgres (and other dbms)

[atulfj]

Problem

The deployment "manager", and more specifically the veraison stores command, can be used to peek into the endorsements & trust anchors store and the policy store. Currently, this is restricted to work with sqlite3 drivers only, as seen in the stores() function (and other functions) of deployments/docker/src/manager-dispatcher. An example:

$_utils_dir/corim-store list triples

reference

We need to provide --dbms and --dsn to list triples stored in a postgres database. But it's not possible through this script.

Similarly for the policy store, sqlite3 is hard-coded into the script:

sqlite3 $_stores_dir/po-store.sql 'select distinct kv_val from kvstore' | jq "$query"

reference

Suggestions

Take the driver and the datasource as parameters. These values can be extracted from the configuration file and used in the manager-dispatcher script.