Remove the `struct Manifest` in `ten_rust` and the `all_fields` field in `struct Property`

[halajohn]

The sole purpose of this field is to preserve the original order of manifest.json and property.json when writing in-memory data back to these files. However, this implementation has poor maintainability. A better approach would be to remove this field—i.e., remove this mechanism—and replace it with the following mechanism:

1. When tman reads in manifest.json and property.json, sort the contents of the JSON files. The sorting rules are as follows:

manifest.json

• Refer to the order in https://github.com/TEN-framework/ten-framework/blob/main/packages/core_extensions/default_extension_cpp/manifest.json for sorting.

property.json

• Refer to the order in https://github.com/TEN-framework/ten-framework/blob/main/tests/ten_runtime/integration/cpp/ffmpeg_basic/ffmpeg_basic_app/property.json for sorting.

2. After sorting in memory in Step 1, if the file content has changed, write it back to the JSON file. If there is no change, do not write back (to avoid changes to file modification time, etc.).