Add avaje-config-toml

[Mechite]

Added TOML support. This supports dotted nesting.

It uses a tiny library, tomlj, not to be confused with toml4j
This library has one dependency, on ANTLR, for parsing, which itself has zero dependencies.

avaje-config-toml->tomlj->antlr4-runtime

Example

(from the test):
Given:

key3 = "c"

[one]
key = "a"
key2 = "b"

When:

var parser = new TomlParser();
Map<String, String> map = parser.load(new StringReader(input()));

assertThat(map).hasSize(3);
assertThat(map).containsOnlyKeys("one.key", "one.key2", "key3");
assertThat(map).containsEntry("one.key", "a");
assertThat(map).containsEntry("one.key2", "b");
assertThat(map).containsEntry("key3", "c");

Then:
test passes

[SentryMan]

Neat

[rbygrave]

I've added a change such that the TomlParser is registered for service loading as a ConfigExtension. If you are happy with that change @Mechite then I think we are good to merge this PR.

[Mechite]

I've added a change such that the TomlParser is registered for service loading as a ConfigExtension. If you are happy with that change @Mechite then I think we are good to merge this PR.

Totally good with it 👍

(I originally, as you likely immediately noticed, cloned the main module, hence the POM, but also, hence not fully understanding or testing the service loading setup.

I just made it pass unit testing, and published PR as an experiment, to see what kind of feedback it gets)