Allow accessing yaml configuration .env.xxx from lua module

[ecerulm]

Is your feature request related to a problem? Please describe.

While using fluentbit yaml configuration you can use

env:
  myvar1: myvalue1

but those values cannot be accessed via lua module today, the following code won't work

          - name: lua
            call: modify
            code: |
              function modify(tag, timestamp, record)
               new_record = {}
               new_record.xxxx = env.myvar1
               return  1, timestamp, new_record
              end

Describe the solution you'd like

I would like a global variable env available while evaluating the lua function giving access to the things defined in the fluent configuration yaml at .env

Describe alternatives you've considered

• hard coding the values in the lua code

Additional context

[edsiper]

tests are welcome: #9617