Helm documentation external db rekor installation

[Omer-Zinman-Intel]

Hello,
We are trying to deploy Rekor + trillian using external redis + mysql databases, and it seems that:

1. rekor chart lacks the appropriate flags to redirect and authenticate to external databases (and put createdb on disabled, which creates a lot of issues). Trillian chart has some tools that allows it to authenticate to external database, however there's no flag to control the database name.
2. In general I didn't find any official documentation (with or without external db) on how to get this up and running. In our case, it keeps hanging on

I am opening this issue as per request on Slack, we need a thorough documentation on how to build the helm command with all the relevant flags (we don't want to start editing the chart, this is not good practice with future releases and we need to avoid it). For any reference we use rancher.

Any help would be much appreciated!