Previously, we were returning an empty optional if key contained a
numerical value which was not stored as double. Stop doing that and
rename the method to signify the change in the behavior.
Apparently, this fixes bug in an InspectorWidget in Ladybird on
Serenity: it showed 0 for element's boxes with integer sizes.
`get()` is intended as a replacement for `get_deprecated()` and `get_ptr
()`. The former returns the same value for "key not found" and "key
found and contains `null`" which is ambiguous. The latter returns a raw
pointer which is spooky. Returning `Optional<JsonValue const&>` covers
all the previous uses for these.
The `get_foo()` methods are helpers to make user code less verbose. Most
of the time, we only want a specific type of value: if we want a number
and get a string, we respond the same as if the value was not there at
all. These make that easier to express.
This also adjusts the `has_i32()` method and friends to examine the
value instead of just looking at the underlying type.
This patch adds JsonValue, JsonObject and JsonArray. You can use them to
build up a JsonObject and then serialize it to a string via to_string().
This patch only implements encoding, no decoding yet.
