DOC-7652: Document how to manage channels via the System Console

[Rutam21]

Summary

Detailed steps for the channel administration workflows were required but absent. So, this PR aims to add the steps for all those workflows for channel management on the User management configuration settings page.

The following workflows have been added.

• Find Channels
• Filter channel searches
• Review channel configuration
• Advanced Access Controls
  • Create Posts
  • Post Reactions
  • Manage Members
  • Channel Mentions
  • Manage Bookmarks
• Channel Management
  • Sync Group Members
  • Public Channel or Private Channel
• Groups (Skipped)
• Members
  • Add a Member
  • Remove a Member
• Archive a channel

Ticket Link

This PR fixes #7652

Checklist

• This PR follows the Mattermost Contributing Guidelines.
• Relevant product screenshots in the Denim theme have been added.
• Workflows are structured as a numbered list for the steps instead of paragraphs.
• The changes are tested using a local build.

[mattermost-build]

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[Rutam21]

@cwarnermm Please review and suggest changes, if any. Thanks.

[github-actions]

Newest code from Rutam21 has been published to preview environment for Git SHA fc76fc3

[cwarnermm]

@Rutam21 - I've provided editorial feedback on this docs PR to align it to our style guide practices. Please use the editorial feedback in this docs PR to inform changes to #7651. Thanks!

[Rutam21]

@cwarnermm Thanks for the review. All the requested changes have been applied, and the PR is ready for your evaluation.

[cwarnermm]

Thanks, @Rutam21!