Feature Request: Allow setting an HTTP proxy on OTLP Exporters

[SpamapS]

opentelemetry-ruby/exporter/otlp/lib/opentelemetry/exporter/otlp/exporter.rb

Line 127 in 245aea5

http = Net::HTTP.new(uri.hostname, uri.port)

We need to be able to configure different exporters to use different proxy configurations. Environment variables are not sufficient.