Add ability to perform custom branding

[stmcginnis]

It would be great to expose a common way to configure branding, both for service provider use and to help differentiate instances across internal teams.

I'd love to see a way to set:

• Top left logo
• Main color
• Potentially favicon image
• Maybe displayed name

Basically, everything that Rancher enables for branding their UI: https://ranchermanager.docs.rancher.com/how-to-guides/new-user-guides/authentication-permissions-and-global-configuration/custom-branding

Probably multiple ways to approach this, but I was thinking something like a SkoonerSetting CRD where you could do something like:

---
apiVersion: skooner.k8s.io/v1beta1
kind: SkoonerSetting
metadata:
  name: skooner-logo
  value: "${BASE64_ENCODED_LOGO}"
---
apiVersion: skooner.k8s.io/v1beta1
kind: SkoonerSetting
metadata:
  name: skooner-color
  value: "${RGB_COLOR}"