fix object store TOML definitions, add test data

[joeshaw]

This fixes the object store configs to match the Viceroy implementation, and adds object store definitions to the test data.

I think it remains an open question as to whether we should change the Viceroy implementation to be more consistent with the existing local server definitions (backends, dictionaries).

[joeshaw]

The inconsistencies I see:

1. The name of the object store section is object_store, singular. backends and dictionaries are plural.
2. Dictionaries are populated with a struct containing a key-value map, whereas object stores are populated with a list of structs. Personally I think the object store implementation is nicer to use, but they are different.
3. For loading data from files, dictionaries uses file and object_store uses path.

Go structure for dictionaries:

type LocalServer struct {
	Backends     map[string]LocalBackend       `toml:"backends"`
	Dictionaries map[string]LocalDictionary    `toml:"dictionaries,omitempty"`
	ObjectStore  map[string][]LocalObjectStore `toml:"object_store,omitempty"`
}

type LocalDictionary struct {
	File     string            `toml:"file,omitempty"`
	Format   string            `toml:"format"`
	Contents map[string]string `toml:"contents,omitempty"`
}

which maps to a toml like:

[local_server]

  [local_server.dictionaries]

    [local_server.dictionaries.toml]
      format = "inline-toml"

    [local_server.dictionaries.toml.contents]
      foo = "bar"
      baz = """
qux"""

Go structure for object stores:

type LocalServer struct {
	Backends     map[string]LocalBackend       `toml:"backends"`
	Dictionaries map[string]LocalDictionary    `toml:"dictionaries,omitempty"`
	ObjectStore  map[string][]LocalObjectStore `toml:"object_store,omitempty"`
}

type LocalObjectStore struct {
	Key  string `toml:"key"`
	Path string `toml:"path,omitempty"`
	Data string `toml:"data,omitempty"`
}

which maps to a toml like:

[local_server]

  [local_server.object_store]

    [[local_server.object_store.store_two]]
      key = "first"
      data = "This is some data"

    [[local_server.object_store.store_two]]
      key = "second"
      path = "strings.json"

or, IMO even nicer:

[local_server]

  [local_server.object_store]
    store_one = [{key = "first", data = "This is some data"}, {key = "second", path = "strings.json"}]

[Integralist]

Thanks @joeshaw PRs are definitely welcomed, especially for the consistency issues which are quite frustrating from a devex perspective 👍🏻

[Integralist]

@chrispoole643 were you documenting the ObjectStore in https://developer.fastly.com/reference/compute/fastly-toml/ ? I thought I recalled you doing so but couldn't see it in there at the moment. At any rate, we'll want to ensure that's kept consistent with what's here ☝🏻

[joeshaw]

I opened fastly/Viceroy#206 to address it. If it's merged I'll adjust things here too.