[PTS-bot] Enable sharding

- Retrieve Pandora Server and Rootcanal ports from args in pts-bot
  command.
- Add an option to create a temp directory to store PTS-bot
  binaries to avoid conflicts when sharding.

Test: atest pts-bot -- --shard-count 5 --shard-index 2
Change-Id: Ifc4059619525ff0b12637339ca8f8c0a7330efae