BUILD - Optimize Dockerfile by using alpine as base image

[Juansecu]

Optimized Dockerfile by using alpine:3 as base image for build and prod stages.

Why is this PR opened as a draft PR?

This is because I talked with @dongresource, and he mentioned that you guys must be sure that changing the datatype of property TIMEOUT from src/settings.hpp to int64_t works and doesn't break anything while running the server application.

This is a PR mainly intended for allowing you all to know by first hand what is necessary for making the optimizations to Dockerfile.

By the way, the changes made to file src/settings.hpp were extracted from the branch win32-x86.