Add DateTime and Time without TimeZone

[yassun7010]

Proposal

I suggest adding date-time-local and time-local to the Format Registry.

I am developing a TOML Language Server with validation feature using JSON Schema.

LocalDatetime and LocalTime are defined in TOML as specifications, but there is currently no corresponding String format in JSON Schema.

I sought help from the JSON Schema community and was referred here.

About naming

date-time-local is named differently from TOML.
I believe it is more consistent with other formats if it is first indicated to be a date.
Also, datetime-local exists in html.