Add 'Reducing the Memory Footprint' page

[maxkernbach]

https://github.com/arangodb/planning/issues/3728

[Simran-B]

@sleto-it Not sure about putting it into the Troubleshooting chapter yet... should it rather be located under Administration or perhaps Tutorials even?

[sleto-it]

Hi @Simran-B I do not think it can be located under Administration, the way it is written. Needs some changes first
Administration is a chapter of the reference manual - the style does not fit, should be changed first

A tutorial probably okay

We should link other section of the documentation (e.g. https://www.arangodb.com/docs/3.4/installation-linux-osconfiguration.html#over-commit-memory) otherwise it seems something included in the doc and unlinked to other - I think we should avoid such situation

Hope the above helps

[Simran-B]

@sleto-it Changed to be added as tutorial, use the summary as introduction, reference the linux os conf page, reworded a few sentences:

7ba0d89