Add avaje-config-json

[Mechite]

An experiment, created a simple parser with jsonb dependency as a separate module.

Did this because I saw #94 was closed, and this seemed like the first simple thing that never got done, adding rudimentary JSON support like another one of the languages here seems quite simple?

If we want to do more advanced stuff, like destructure a more nested JSON structure into key/value with . to seperate the levels. for example:

{
    "postgresql": {
        "host": "127.0.0.1"
    }
}

to be destructured into
"postgresql.host" = "127.0.0.1"
in the Map<String, String>,

this pull request does not achieve that. It will only support a flat JSON structure.
I didn't check what the YAML parser does.

Go ahead and make changes to this PR if you think it's a good idea, close it if not

[Mechite]

EDIT - Moved to #172
(this PR originally brought #172 in along with it. It has been separated out)

[SentryMan]

I'm not totally sold on json as a config, @rbygrave what do you think?

[rbygrave]

For myself, I'm personally extremely unlikely to use json for configuration of a Java application (where we have properties files which are so simple).

I'm happy to merge and include this if someone is going to say that they will actually use it? If no one has any immediate use case for this then I'm also happy for this PR to sit here for a bit and see what comments it gets.

[agentgt]

@SentryMan @rbygrave @Mechite

For me the challenge in config is not so much formats (parsing) but where the key values are coming from and if they have to be transformed. See #175

That is the source from where it comes from more often dictates what its format is anyway so I just don't find JSON config useful either.

[Mechite]

@agentgt Absolutely agreed. I think even for an extremely large set of configurations, migrating formats would be more than trivial, even with special types like datetime being used with formats that support it.