Add recommended HDD space when building the project

[sxiii]

What I'd like: The documentation isn't telling anything about the build size. First, I cleared up 10 GBs. It failed. Then I cleared 30 GB. It failed again. I think the BUILDING documentation markdown file should include a section on how much space will the build take so people are ready to free like 40 or 50 GBs and not follow my errors.

[zmrow]

Thanks for the recommendation! Another user commented about the same issue and there's currently a PR (#1107) to address it!