ThemisToDiscord

Improvements

- Implements numerous efficiency optimizations - Constructs a JSON template once per message during initialization instead of constructing every time the message executes - Expands all placeholders in the entire JSON template instead of per field - Utilizes the correct String replace method, replace instead of replaceAll for literal replacement, completely eliminating the overhead of creating Regex/Pattern objects - Ensures execution pools are isolated and thread safe - Integrates a self-cleaning Guava cache to prevent data accumulation on long-running/high-volume servers - Ensures all threads are shutdown gracefully when the plugin is disabled - Adds optional anonymous metrics gathering via [bStats](https://bstats.org/)

Development

- Migrates from Maven to Gradle - Refactors the Message class for better maintainability - Introduces the HandlingService and EmbedUtil classes for greater separation of concerns and closer adherence of the single responsibility principle - Breaks methods up to reduce their sizes for better readability - Eliminates the use of two nested lists (lists of lists) by utilizing small efficient record classes Related PR: #8