[Draft] Add different file sizes to Milestone Smoke Test

[significance]

It is important to monitor performance for various file sizes passing through the Milestone Smoke Test. At present only one file size is tested.

Implement extra tests, via appropriate parameterisation to upload and download in the same way files with sizes approx:

3kb
30kb
300kb
30mb
100mb
300mb

If plausible higher filesizes could also be considered.

@nugaon 👁️ also if possible different erasure code levels, and perhaps for filesizes to fit in with the erasure code tests that have been run manually