Cannot load commit files with values of type xsd:time, xsd:dateTime, xsd:date

[mpoffald]

Similar to https://github.com/fluree/core/issues/31, we are writing out time values incorrectly, creating unparseable commit files

(do
    (def conn @(fluree/connect {:method :file
                                :storage-path "dev/data" 
                                :defaults
                                {:context (merge test-utils/default-str-context {"ex" "http://example.org/ns/"})}}))
    (def    ledger @(fluree/create conn "user/test"))
    (def    db @(fluree/stage
                  (fluree/db ledger)
                  [{"@id" "ex:Foo",
                    "@type" "ex:Bar",
                    "ex:offsetDateTime" {"@type" "xsd:dateTime"
                                         "@value" "2023-04-01T00:00:00.000Z"}
                    "ex:localDateTime" {"@type" "xsd:dateTime"
                                        "@value" "2021-09-24T11:14:32.833"}
                    "ex:offsetDateTime2" {"@type" "xsd:date"
                                          "@value" "2022-01-05Z"}
                    "ex:localDate" {"@type" "xsd:date"
                                        "@value" "2024-02-02"}
                   "ex:localTime" {"@type" "xsd:time"
                                    "@value" "12:42:00"}
                    "ex:offsetTime" {"@type" "xsd:time"
                                     "@value" "12:42:00Z"}}]))
    (def    db-commit @(fluree/commit! ledger db)))  

  (def    loaded @(fluree/load conn (:alias ledger)))  

;;=> Exception in thread "async-dispatch-5" com.fasterxml.jackson.core.JsonParseException: Unexpected character ('#' (code 35)): expected a valid value (JSON String, Number, Array, Object or token 'null', 'true' or 'false')

In the commit file:

[{"@id":"http://example.org/ns/Foo","@type":"http://example.org/ns/Bar",
"http://example.org/ns/localDate":{"@value":#object[java.time.LocalDate 0x7b1cb6fd "2024-02-02"]},
"http://example.org/ns/localDateTime":{"@value":#object[java.time.LocalDateTime 0x321437aa "2021-09-24T11:14:32.833"]},
"http://example.org/ns/localTime":{"@value":#object[java.time.LocalTime 0x757a6c8e "12:42"]},
"http://example.org/ns/offsetDateTime":{"@value":#object[java.time.OffsetDateTime 0x2ca1c44b "2023-04-01T00:00Z"]},
"http://example.org/ns/offsetDateTime2":{"@value":#object[java.time.OffsetDateTime 0x3d3ec897 "2022-01-05T00:00Z"]},
"http://example.org/ns/offsetTime":{"@value":#object[java.time.OffsetTime 0x6710cb38 "12:42Z"]}}]