[self hosted] Share some color about practical limits and table sizes

[fulldecent]

For the SaaS product, the documentation clearly explains the table size limits. This includes hard limits like the 5,000 rows for free plan, 100,000 rows for paid. And importantly, it even has useful color, showing it's about 20MB of CSV-sized data. Great! ❤️

I am considering to use the self-hosted install and reading the documentation for that. It also has great notes about what to expect, like hardware requirements. And then there are notes about typical performance, that's great!

Maybe the self hosted documentation can please also add some notes about scalability. If I have ten users simultaneously using a table with 100,000 rows, will that work on a typical "minimal spec" server? or is caching and a beefier setup required? Is there some basic idea about which things contribute to performance limits?

Sizing up the performance capabilities and limits is an important step for any company considering to migrate to Grist, so I hope this information can help other new people considering the project, and considering if they want self-hosted or SaaS.