Rework DurationFormatter to allow for more abstract implementations

[Exloki]

I debated deprecating the existing enumeration support, but I don't think it's necessary as they still serve a convenience purpose and help improve code clarity most the time.

I did run the following highly professional unit tests to confirm functionality:

System.out.println("CTest 1: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), true, 1));
System.out.println("CTest 2: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), true, 2));
System.out.println("CTest 3: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), true, 3));
System.out.println("CTest 4: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), true, 4));
System.out.println("CTest 5: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), true));
System.out.println("CTest 6: " + DurationFormatter.format(Duration.of(-1, ChronoUnit.SECONDS), true));

System.out.println("LTest 1: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), false, 1));
System.out.println("LTest 2: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), false, 2));
System.out.println("LTest 3: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), false, 3));
System.out.println("LTest 4: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), false, 4));
System.out.println("LTest 5: " + DurationFormatter.format(Duration.of(1337420, ChronoUnit.SECONDS), false));
System.out.println("LTest 6: " + DurationFormatter.format(Duration.of(-1, ChronoUnit.SECONDS), false));

System.out.println("OTest 1: " + DurationFormatter.CONCISE.format(Duration.of(1337420, ChronoUnit.SECONDS)));
System.out.println("OTest 2: " + DurationFormatter.CONCISE_LOW_ACCURACY.format(Duration.of(1337420, ChronoUnit.SECONDS)));
System.out.println("OTest 3: " + DurationFormatter.LONG.format(Duration.of(1337420, ChronoUnit.SECONDS)));

Which functioned as expected:

[16:20:07 INFO]: CTest 1: 2w
[16:20:07 INFO]: CTest 2: 2w 1d
[16:20:07 INFO]: CTest 3: 2w 1d 11h
[16:20:07 INFO]: CTest 4: 2w 1d 11h 30m
[16:20:07 INFO]: CTest 5: 2w 1d 11h 30m 20s
[16:20:07 INFO]: CTest 6: 0s

[16:20:07 INFO]: LTest 1: 2 weeks
[16:20:07 INFO]: LTest 2: 2 weeks 1day
[16:20:07 INFO]: LTest 3: 2 weeks 1day 11 hours
[16:20:07 INFO]: LTest 4: 2 weeks 1day 11 hours 30 minutes
[16:20:07 INFO]: LTest 5: 2 weeks 1day 11 hours 30 minutes 20 seconds
[16:20:07 INFO]: LTest 6: 0 seconds

[16:20:07 INFO]: OTest 1: 2w 1d 11h 30m 20s
[16:20:07 INFO]: OTest 2: 2w 1d 11h
[16:20:07 INFO]: OTest 3: 2 weeks 1day 11 hours 30 minutes 20 seconds