Documentation is too big

The documentation preview from https://github.com/jump-dev/JuMP.jl/pull/3478 failed to build because it's very big:
https://github.com/jump-dev/JuMP.jl/actions/runs/6054461407/job/16431976144


I've gone and removed some old previews, but we should consider removing some old versions.

Do we need https://jump.dev/JuMP.jl/v0.19.2/ or as far back as https://jump.dev/JuMP.jl/v0.12/?

Perhaps we could just keep the latest patch release for each minor and redirect.

Each copy of the documentation is ~21 Mb, so we can have ~50 copies before we hit 1 Gb.

```Julia
(base) oscar@Oscars-MBP JuMP % du -sh v1.14.0
21M v1.14.0
(base) oscar@Oscars-MBP JuMP % du -sh v1.14.0/*
4.2M v1.14.0/JuMP.pdf
608K v1.14.0/api
1.5M v1.14.0/assets
40K v1.14.0/background
156K v1.14.0/changelog
260K v1.14.0/developers
64K v1.14.0/extensions
36K v1.14.0/index.html
56K v1.14.0/installation
588K v1.14.0/manual
2.7M v1.14.0/moi
1.8M v1.14.0/packages
228K v1.14.0/release_notes
3.0M v1.14.0/search_index.js
36K v1.14.0/should_i_use
4.0K v1.14.0/siteinfo.js
5.5M v1.14.0/tutorials
```

We could also redirect all of the PDFs to the latest copy, rather than storing a 4 Mb PDF for every version.

cc @mortenpi