Create cross-platforms build script

[GregoryAlbouy]

Description

By default, go build build a binary that is only executable by the machine's platform (using environment variables GOOS and GOARCH that are specific to the machine).
We want the binary to be executable on most machines, hence we need a script to make cross-platforms builds.

Tasks

• Create a script that builds benchttp binaries for the following platforms:
  • darwin/amd64
  • darwin/arm64
  • linux/386
  • linux/amd64
  • linux/arm
  • linux/arm64
  • windows/386
  • windows/amd64
• Update Makefile so it calls that script

Suggestions

Notes

• Do not forget to add build tag prod so it uses the correct environment (benchttp endpoint instead of local dev server)