Add Bandwidth File KeyValues showing relays' ratios and network averages

As commented at tpo/network-health/sbws#40156 (closed)

added Sponsor 112 Q2 S112-O3 labels

assigned to @juga

changed time estimate to 1h

added Doing label

mentioned in merge request !148 (closed)

mentioned in merge request !149 (merged)

mentioned in issue tpo/network-health/metrics/descriptorParser#45 (closed)

mentioned in issue tpo/network-health/metrics/collector#40033 (moved)

closed with merge request !149 (merged)

mentioned in commit 7ceb6852

mentioned in issue tpo/network-health/metrics/library#40020 (closed)

added 30m of time spent

Added time spent in June

mentioned in commit trinity-1686a/torspec@d1259b62