Problems:
- All dependencies and targets were out of date.
- File had mixed-usage of whitespacing, breaking standard.

Changes:
- Bump 'java.version' property to '17' (from '1.16') [Sync w/ Towny 0.100.4.0
- Bump Bukkit API version to '1.19' (from '1.15') [Sync w/ Towny 0.100.4.0]
- Update 'spigot-api' to '1.20.4-R0.1-SNAPSHOT' (from '1.16.5') [Sync w/ Towny 0.100.4.0]
- Bump 'towny.version' property to '0.100.4.0' (from '0.100.2.0')
- Added Property: 'dynmapapi.version', set to '3.6'
- Apply useage of 'towny.version' property for the towny dependency's version.
- Added DynmapCoreAPI (dynmap-api stopped pulling it in as a transient dep)
- Apply	'dynmapapi.version' property to	both 'dynmap-api' and 'DynmapCoreAPI'
- Bump 'pl3xmap' version to '1.20.4-492' (from '1.20.4-476')
- Bump 'bluemap-api' to '2.7.0', targeting Bluemap v5+ (from 'v2.5.1',
  targeting Bluemap v3.14+)
  - Note: Bluemaps no longer builds on Jitpak. Need to migrate on next Towny stable release.
- Bump squaremap-api to '1.3.2' (from '1.1.12')
- Update maven-build-plugin to use the 'java.version' property (was using '1.8')