Use an environment variable in BlueaAPI to get beamline+hutch

[olliesilvester]

See #29 (comment)

[noemifrisina]

Set the beamline via an environment variable in the blueapi helmchart, eg for vmxm:

blueapi:
  extraEnvVars: 
    - name: BEAMLINE
      value: i02-1
    - name: ZOCALO_CONFIG
      value: /dls_sw/apps/zocalo/live/configuration.yaml

so we don't have to pass it to log set up every time but can just read it.

[noemifrisina]

NOTE. This would be useful for more than just logging