Kratos SMTP password value needs to be URL encoded

Our Kratos Courier initialization failed because there was a forward slash in the password. It also failed on another character when I deleted the forward slash.

This is because you configure Kratos with a connection URI that contains all the information about the SMTP connection in one string:

smtp://username:password@server:port/

We currently just throw in the outgoing_mail_smtp_password, but we need a version of it that's URLencoded.

Unfortunately, because it's something that we need to put in the values file, we can't use helm templates to fix this. Flux doesn't allow us to manipulate the value either, so the only solution I've come up with so far is to add a second variable for the URL encoded version of the SMTP password to the stackspin-cluster-variables secret. That, or not allow any special characters in the password in the first place...