Provision freedesktop-sdk performance benchmarking

[See original issue on GitLab](https://gitlab.com/BuildStream/buildstream/-/issues/1153)
In GitLab by [[Gitlab user @traveltissues]](https://gitlab.com/traveltissues) on Oct 2, 2019, 21:15

Now that we've seen some performance regression in the case of `bst show` in the freedesktop-sdk project I think there's value in analysing that and identifying the sources of stress. There is probably a case for adding this case to regular performance benchmarking on some interval of commits.

Start by reproducing and analysing the reported performance regression in `bst show` for the freedesktop-sdk project, then identify the sources of stress. Define what recurring benchmark should run and how it should detect regressions across intervals of commits; no files or tests are named in the issue.

Written by the indexing model from the issue text.