Adapt "field" terminology in the spec to canonical JSON terminology

As a continuation of #66...

I have just noticed that the JSON spec does not use "field", 4, which is the term used in the current (0.6dev3) version of the OME-Zarr spec.

Fromk the JSON spec:

Objects:

An object structure is represented as a pair of curly brackets
surrounding zero or more name/value pairs (or members). A name is a
string. A single colon comes after each name, separating the name
from the value. A single comma separates a value from a following
name. The names within an object SHOULD be unique.

So if we are being precise, a sentence like

• "MUST be an array. Each element MUST be an object containing the fields input_axes, output_axes, and transformation."

should become:

• "MUST be an array of objects. Each object MUST contain name/value pairs with names input_axes, output_axes, and transformation."

or

• "MUST be an array of objects. Each object MUST have members named input_axes, output_axes, and transformation."

Another option is to use "property" (or even " name/value pairs ") and define it clearly elsewhere. That is what the JSON Schema spec does in 4.2.1:

object:
An unordered set of properties mapping a string to an instance, from the JSON "object" value

Start by reviewing the OME-Zarr specification discussed in this issue and RFC 8259 section 4, then search the spec for uses of “field.” Update JSON terminology consistently to “members,” “properties,” or “name/value pairs,” and consider the context from issue #66. Done means the relevant specification text uses precise, consistent terminology.