Timing info on 1st big retiling run

[dhardestylewis]

to generate Texas-wide VRTs :

Queue	Wall time (ms)	SUs
long	432008000	96.001

to retile Texas-wide :

Queue	Wall time (ms)	SUs
long	133559000	504.556
long	139992000	995.498

[dhardestylewis]

• [x] update README to reflect these stats

[dhardestylewis]

✅ README_LONG updated here 👉 https://github.com/dhardestylewis/terrain_aggregator#the-terrain-aggregator

• [ ] Stats not yet broken out or referred back to in description of workflow or costs of each workflow step

[dhardestylewis]

• [ ] this issue will be kept open until stats available from https://github.com/dhardestylewis/terrain_aggregator/issues/71#issuecomment-1220116529