add web url config options

[wkloucek]

Description

expose more web url config options

Related Issue

• Fixes Support Web post logout URI #337
• Fixes Support Web "logged out url" #334
• Fixes Support Web imprint and privacy url #333
• Needs fix WEB_OPTION_ACCESS_DENIED_HELP_URL ocis#6852 for the postLogoutRedirectURI to work. For test purposes the image wkloucek/ocis:2023-07-19.1 can be used

Motivation and Context

How Has This Been Tested?

set this values:

services:
  web:
    config:
      postLogoutRedirectURI: https://ocis.kube.owncloud.test/thisisacustompostlogouturi
      accessDeniedHelpURL: https://foo.bar/accessdenied
      imprintURL: https://foo.bar/imprint
      privacyURL: https://foo.bar/privacy

Screenshots (if appropriate):

(just go to https://ocis.kube.owncloud.test/access-denied and you'll see the "More" / "Mehr anzeigen" only if accessDeniedHelpURL is set)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Technical debt
• Tests only (no source changes)

Checklist:

• Code changes
• Unit tests added
• Acceptance tests added
• Documentation generated (make docs) and committed
• Documentation ticket raised:
• Documentation PR created:

[d7oc]

LGTM aside the comment about the description format.