Currently, credentials are store in the registry, ie a table in database.

Let's move them to Vault.

Plan is:

• create a Vault client in TCL, release it into tcllib or as standalone package if not possible
• provide helper TCL commands specific to our eggdrop logic to help to connect and retrieve secret from apps/viperserv/
• configure eggdrop to read approle credentials from a file provisioned through viperserv role in rOPS
• move credentials to Vault
• test it with active stuff (nickserv, MySQL, RabbitMQ)