refactor: use xanthic cache facade

[iProdigy]

Prerequisites for Code Changes

• This pull request follows the code style of the project
• I have tested this feature

Issues Fixed

• Forced Caffeine use was incompatible with Android

Changes Proposed

• Switch all direct Caffeine use to the Xanthic facade

Additional Information

For now, we still depend on cache-provider-caffeine to avoid any breaking changes... users can exclude this dependency & specify a different provider

[PhilippHeuer]

Should we also allow to explicitly set a provider in the builder?

[iProdigy]

Should we also allow to explicitly set a provider in the builder?

We have some static final caches where it'd be tricky to pass that state to (e.g., https://github.com/twitch4j/twitch4j/blob/refactor/xanthic-cache/eventsub-common/src/main/java/com/github/twitch4j/eventsub/util/EventSubVerifier.java#L35)

So users can just do CacheApiSettings#setDefaultCacheProvider instead