CI: minimize resource usage - simplify builds

[RandyMcMillan]

WIP: simplify CI builds to not exceed free tier

plebnet-playground-docker/.github/workflows/plebnet-playground.yml

Line 66 in 85177e0

./uninstall.sh

[RandyMcMillan]

plebnet-playground-docker/.github/workflows/plebnet-playground.yml

Line 88 in 85177e0

play bitcoin 'bitcoin-cli getblockhash 1000'

[RandyMcMillan]

I have some ideas...