Add CSP headers

[cstns]

Description

Take CSP into consideration and allows the editor to be embedded

Related Issue(s)

related to: #3801
part of: #3800

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• Backport needed? -> add the backport label
• Includes a DB migration? -> add the area:migration label

[cstns]

We may even be able to allow them to self configure and overwrite the config if needed.

The less config needed to be done by the end user, the better!

[joepavitt]

@cstns now that you're back from holiday - what's the status on this?

[cstns]

Not looking good. Spoke with @hardillb about it and it seems it's the oauth lib that we're using is causing the issues. I also stumbled across jaredhanson/passport#938 in which the author seems to take his hands of the wheel