[Enhancement]: Shrink size of core-jar / Rethink shading

[AB-xdev]

Module

Core

Proposal

The testcontainers jar file currently has a size of a whopping 17MB (packed; unpacked 34MB), making it by far one of the biggest maven dependencies I know of.

Most of the size (>97%; 33MB) seems to come from shaded artifacts inside org.testcontainers.shaded.

A full list of disadvantages of shading can be found in JLBP-18.

I think the jar could be a lot smaller. Here a few ways how this could be tackled:

• Check if all the shaded dependencies are required in the core module in the first place. I check the core module and couldn't find any class that implements: org.hamcrest, org.checkerframework, org.bouncycastle or org.awaitability.
  There are also other libraries that could be easily replaced, e.g. guava as it's only used in a few places and uses nowadays standard java stuff. Removing these 5 libs alone would shrink the lib by 23MB or 67% alone.
• Maybe don't use shading at all and publish a bom that contains the exact versions of the required dependencies, that way there should also be no dependency conflicts