[RFE] Allows the user to custom helm install args when install the app

[liuweiGL]

Is your feature request related to a problem? Please describe.

The bitnami/charts always has so many properties in "values.yaml", so i will pick some common properties to set the default values and record them in my documentation. In this way, my partners just need to modify a few items(eg password) then copy and paste them into rancher-dashboard to complete the installation.

When I replaced the values.yaml content with a fragment copied from my documentation, Due to rancher use --values instead of -f flag in the helm install command, helm chart can't get the full values causing the template to report errors, like "nil pointer evaluating interface {}.debug".

Describe the solution you'd like

Allow me choose -f or --values flag to exec the helm install command.

Describe alternatives you've considered

Add a option in this page:

Additional context
For example, the configuration of the MySQL chart has over 460 lines:

But all I need are the following few dozen items:

When i use configuration fragment copied from my documentation to install the mysql app:

Template parsing errors are reported because the original values are overwritten instead of merged: