feat: standalone targeting, fractional shorthand

[toddbaert]

This PR does 2 things:

• Allows for fractional targeting shorthand where no weight (assumes weight = 1)
• Allows the targeting.json schema to be used alone, not just as part of the flag definition schema

Non functionally, it restructures our testing so that tests pertaining to targeting.json exist in the test/targeting/ dir, while tests pertaining to the flags.json exist in the test/flags dir.

Fixes: #165

[toddbaert]

This allows for the use of targeting by itself.

[toddbaert]

All these tests used to be embedded in flag json objects, which was not necessary for testing the targeting. This PR converts all tests which just test targeting validation to purely targeting tests, since we can now validate targeting alone.

[toddbaert]

This allows for the fractional shorthand support (no wieght == weight 1)

[toddbaert]

This is the only net-new test.

[aepfli]

i do not think this is actually what we want. this validates an object with a property targeting like

{
  "targeting": {
    "ifddd": [
      {
        "starts_with": [
          {
            "var": "id"
          },
          "abc"
        ]
      },
      "prefix",
      "else"
    ]
  }
}

see https://www.jsonschemavalidator.net/s/yRS6TJ9g -

but what we actually want is a validation without the targeting property like in proposed in #165 (comment) something like

{
  "ifddd": [
    {
      "starts_with": [
        {
          "var": "id"
        },
        "abc"
      ]
    },
    "prefix",
    "else"
  ]
}

[toddbaert]

Absolutely correct, thanks a lot.

I've made this change.

[aepfli]

so far the code and test changes do look good, but i do think we should change the schema changes, to not need the property

[aepfli]

Suggested change

	"properties": {
	"targeting": {
	"$ref": "#/definitions/targeting"
	}
	},
	"anyOf": [
	{
	"$ref": "#/definitions/targeting"
	}
	],

[toddbaert]

Oh you're totally right. I've corrected this and updated all the tests!