Support LiteLoader again by improving processor selection logic

Fix argument passing & add back commandline for legacy versions ...

- Game/jvm arguments are now passed one-at-a-time, never grouped
- Added support for legacy version manifests by adding in the missing
arguments
- Correctly pull arguments from old manifests
- Some slightly hacky handling for old library stanzas
- Short-circuit if library URL has empty path to prevent accidentally
downloading HTML pages as jars
- Add launcherShortname prop, passed to --versionType

Refactor loader processing into subclasses for greater flexibility

Skip extra files that are server-only

Update launcher/runner component to new models ...

- Fix game arguments being missing from version manifest due to new format
- Update Runner to use more substitutions & support new argument model
- Move loader/installer libraries to their own section to avoid runtime conflicts
- Implement some basic feature matching for arguments

Initial 1.16 update ...

oh lord okay
- Update to new launchermeta endpoint for version manifests
- Fix library handling (libraries now seem to give us the URL most of the time)
- Write entire new system for handling the forge installer process
- Fix asset handling, mostly (still TODO is remove all traces of assetSource, it's given to us by launchermeta now)

Update to Java 9/10. Fancy version is still broken.

[Creator] Don't re-download mods using a download URL every time.

Fix URL override still resulting in a (broken) file copy.

Add new creator tools.

Expand the build tools to encompass many more tasks.

Correct location/to mix-up ...

If .url.txt is used, the manifest file should specify that as the download location, not the local "to" location

Switch to Gradle. Use git log --follow for history. ...

This converts the project into a multi-module Gradle build.

By default, Git does not show history past a rename, so use git log
--follow to see further history.