MODE-2674 Adds the ability to pass custom Hikari configuration options to the relational db provider It configures the "minimumIdle" property to a default of 1, meaning only 1 idle connection should be in the pool at any time. It changes the structure of the WF kit by removing the custom Hikari module (which had just 1 resource) and moving that dependency inside the persistence-relational module. It also updates the Hikari version to 2.6.1.