feat: Data object for Service properties

Dear implementers,
it appears to me that the Data object for the Services property is not correctly implemented (see https://cyclonedx.org/docs/1.6/json/#services_items_data).
I am trying to instantiate a Service, and upon populating the data property, I get this hint from the docs


The DataClassification class is defined as
```py
@serializable.serializable_class
class DataClassification:
"""
This is our internal representation of the `dataClassificationType` complex type within the CycloneDX standard.

DataClassification might be deprecated since CycloneDX 1.5, but it is not deprecated in this library.
In fact, this library will try to provide a compatibility layer if needed.

.. note::
See the CycloneDX Schema for dataClassificationType:
https://cyclonedx.org/docs/1.4/xml/#type_dataClassificationType
"""

def __init__(
self, *,
flow: DataFlow,
classification: str
) -> None:
self.flow = flow
self.classification = classification

@property
@serializable.xml_attribute()
def flow(self) -> DataFlow:
"""
Specifies the flow direction of the data.

Valid values are: inbound, outbound, bi-directional, and unknown.

Direction is relative to the service.

- Inbound flow states that data enters the service
- Outbound flow states that data leaves the service
- Bi-directional states that data flows both ways
- Unknown states that the direction is not known

Returns:
`DataFlow`
"""
return self._flow

@flow.setter
def flow(self, flow: DataFlow) -> None:
self._flow = flow

@property
@serializable.xml_name('.')
@serializable.xml_string(serializable.XmlStringSerializationType.NORMALIZED_STRING)
def classification(self) -> str:
"""
Data classification tags data according to its type, sensitivity, and value if altered, stolen, or destroyed.

Returns:
`str`
"""
return self._classification

@classification.setter
def classification(self, classification: str) -> None:
self._classification = classification

def __eq__(self, other: object) -> bool:
if isinstance(other, DataClassification):
return hash(other) == hash(self)
return False

def __lt__(self, other: object) -> bool:
if isinstance(other, DataClassification):
return _ComparableTuple((
self.flow, self.classification
)) < _ComparableTuple((
other.flow, other.classification
))
return NotImplemented

def __hash__(self) -> int:
return hash((self.flow, self.classification))

def __repr__(self) -> str:
return f''
```
Which seems to be missing the "source" and "destination" properties.

This my poetry.lock entry for cyclonedx-python-lib
```toml
name = "cyclonedx-python-lib"
version = "7.6.0"
description = "Python library for CycloneDX"
optional = false
python-versions = "<4.0,>=3.8"
files = [
{file = "cyclonedx_python_lib-7.6.0-py3-none-any.whl", hash = "sha256:30655e89e5f987dc8d57835919748d71589fafeb33ff1dec45048eb72eda3cf9"},
{file = "cyclonedx_python_lib-7.6.0.tar.gz", hash = "sha256:fa481d5f0d82728cb6a32e55f8ba9c666ba75a2bd99eb643228e3011c56bb5c4"},
]
```

Would it be possible for you to adjust this, or let me know what I could do otherwise? Thank you!

Bắt đầu với lớp DataClassification và thuộc tính dữ liệu của Service, sau đó so sánh cách biểu diễn của chúng với services schema JSON CycloneDX 1.6 được liên kết trong issue. Xác nhận source và destination được kỳ vọng xuất hiện như thế nào, và coi công việc hoàn tất khi dữ liệu Service hỗ trợ các trường bắt buộc của schema và kết quả serialization khớp với schema đó.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.