Post bandwidth info for spruce_all_lines

Work towards lhcb-dpa/project#199.

Currently the test spruce_all_lines measures the total bandwidth and print some info in run.log.

The ThroughputProfileHandler is now updated accordingly to post this info to GitLab MR and Mattermost.

This is only implemented for Sprucing at the moment. The tolerance of the throughput is also increased (1% -> 2.5%).

cc @nskidmor