Deployment documentation updates

[nickmisasi]

Summary

I took a pass of each of the main installation methods, and performed a dry run on a new EC2 instance for each. I have made some documentation updates. For most of these updates, it's primarily for clarity. I also made some adjustments to split out some things that are repeatedly written between the various deployment methods to be more DRY.

The most major change was the overhaul of the Docker deployment. The current docs "for production use" have the reader deploy Mattermost and its database on the same instance. This isn't the best advice in production. I've split the documentation into 2 paths here - Quick Start (essentially the existing docs), and Production Use (adjustments to only deploy the Mattermost application container, suggesting external hosting for db and storage). These changes require

Ticket Link

https://mattermost.atlassian.net/browse/CLD-8785
https://mattermost.atlassian.net/browse/CLD-8848
https://mattermost.atlassian.net/browse/CLD-8849
https://mattermost.atlassian.net/browse/CLD-8850
https://mattermost.atlassian.net/browse/CLD-8851
https://mattermost.atlassian.net/browse/CLD-8852
https://mattermost.atlassian.net/browse/CLD-8853

[github-actions]

Newest code from mattermost has been published to preview environment for Git SHA 7e0a17e

[github-actions]

Newest code from mattermost has been published to preview environment for Git SHA 39bb3de

[cwarnermm]

This is a great docs PR, @nickmisasi! I pulled your branch down and applied fixes to build errors and warnings where needed. Remind me: what's the goal of this docs update? What are we trying to achieve? That will help me formulate potential next step recommendations.

[github-actions]

Newest code from mattermost has been published to preview environment for Git SHA a77022b

[nickmisasi]

@cwarnermm High level, this is intended to make it easier to deploy Mattermost. The main focus was on clarity, as well as making sure that our recommendations are not only correct, but actually work (without prior knowledge of deploying Mattermost itself)

[cwarnermm]

@nickmisasi - Thank you! From my perspective, the content of this docs PR is excellent. No concerns at all. I know our structure and navigation needs work, but that's beyond the scope of this lift. Does it make sense to add customer-facing stakeholders as additional technical reviewers at this time? Are there specific perspectives you're looking for prior to us publishing these details?

[cwarnermm]

@nickmisasi - One outstanding thing we'll need to address in this docs PR is H2 redirects. This is something we'll do last, once all stakeholder input is incorporated. I can help with this final step.

[nickmisasi]

@cwarnermm I think it's a good idea to get some stakeholders to view this. Particularly I'd like eyes from @mrckndt, as he has some past work on Docker docs and is probably most familiar with RHEL. I'm open to others if you have anyone in mind. I'll also loop in @toninis as we discussed the Docker docs updates in Hub.