Docs: Add redaction feature

[aeluce]

Description:

Adds documentation for field redaction, both for the new UI workflow and when working with specification files.

Will merge following the release of estuary/ui#1830

Documentation links affected:

Creates a new page at: https://docs.estuary.dev/security/redaction

Also updates a couple related pages to help route interested users to the redaction feature.

Notes for reviewers:

Thanks for reviewing!

[github-actions]

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[travjenkins]

One overall thought I have here is wondering if we should leave this under security?

It 100% makes sense that if someone is reading about security they should know we allow this. However, this feels like in the long run it should live closer to other config stuff. I am initially leaning towards it being under Advanced Features and the security page is a quick landing page that links there (gross) or just redirects (also gross)

[aeluce]

Thanks for looking things over! I could certainly see it being under Advanced Features since it is a feature guide. I'll plan to move it unless anyone chimes in with other opinions.

To confirm the accuracy of the specification file section, @jgraettinger checking if this aligns with your intentions for the redaction feature? Or @jonwihl - is this basically how you instruct users to redact properties in the spec?