Environment variable interpolation in bridge config

[jdcrouse]

Component(s)

opamp bridge

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

I want to populate headers in the opamp bridge from environment variables. The opamp bridge should be able to substitute environment variables during config generation

Describe the solution you'd like

The LoadFromFile function should substitute templated environment variable names with their assigned value using the go os package

Describe alternatives you've considered

No response

Additional context

No response