Add disk space requirements to code quality doc

What does this MR do?

CodeQuality reports can be quite large if your ruleset and project are both large. This causes issues when users pipelines fail and it is difficult to tell it might be because of running out of disk space. This MR adds a note about the disk space requirement using GitLab.com's disk usage as an example. In the future we will update this documentation to include more examples from different size projects as a part of #39998 (closed)

This closes #8008 (closed)

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Does this MR meet the acceptance criteria?

Conformity

• Documentation (if required)