docs: add deployment guide

[tabathad]

Part of #1325, complements #1335.

Adds a deployment guide covering:

• Prerequisites
• Quick start walkthrough
• Docker deployment
• Git client configuration
• Production considerations

Also adds the deployment page to the docs sidebar.

[netlify]

❌ Deploy Preview for endearing-brigadeiros-63f9d0 failed. Why did it fail? →

Name	Link
🔨 Latest commit	2dfb917
🔍 Latest deploy log	https://app.netlify.com/projects/endearing-brigadeiros-63f9d0/deploys/69aef8ace5597e0008e6c108

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.01%. Comparing base (90df884) to head (2dfb917).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1385   +/-   ##
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  Coverage   90.01%   90.01%           
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  Files          67       67           
  Lines        4769     4769           
  Branches      885      885           
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  Hits         4293     4293           
  Misses        458      458           
  Partials       18       18           

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[jescalada]

Looks good so far! Just wondering if we could look into the config loading issue - although it might be because I tested on v1.19.2 rather than the latest rc...

As for the Docker part, I'll do some more setup testing later so we can refine this 👍🏼

[kriswest]

Love to see this going in for v2 and would also like to know why the preview build is failing.

I think we could include some content on loadbalancing. I think the app should loadbalance fine (when using Mongodb) - even if you usually only have one node, knowing that you can deploy a second would enable zero-downtime deployments. I'll raise an issue to check if anyone is actively doing this with their deployment.

Edit: I note the comment about MongoDB being required for multi-instance deployments. We could go a little further as Git proxy does use local storage during processing but its ephemeral at the moment and relates to only a single request (doesn't need to persist). That will not change with @fabiovincenzi's caching contribution - it just means the nodes will have different caches (and you may want to latch users to particular nodes where possible to make best use of caches).