Cyphernode v0.8.1

This is a minor release of a few fixes and improvements:

• Fixed: full compatibility with docker-compose was lost in v0.8.0 (thanks @BHodl)

• Improved: ln_pay now pays using the pay plugin first (with MPP), then legacypay on failure

• Improved: moved env variables from docker-compose.yaml to env files, for proxycron only for now (thanks @phillamy)

• Small improvements in the startup scripts

• Removed inserting previous txs in database when computing a tx fees