feat(sepc): update type meta field info spec

[chaokunyang]

What does this PR do?

Update type meta field info spec:

- field info:
    - header(8
      bits): `3 bits size + 2 bits field name encoding + polymorphism flag + nullability flag + ref tracking flag`.
      Users can use annotation to provide those info.
        - 2 bits field name encoding:
            - encoding: `UTF8/ALL_TO_LOWER_SPECIAL/LOWER_UPPER_DIGIT_SPECIAL/TAG_ID`
            - If tag id is used, i.e. field name is written by an unsigned varint tag id. 2 bits encoding will be `11`.
        - size of field name:
            - The `3 bits size: 0~7`  will be used to indicate length `1~7`, the value `7` indicates to read more bytes,
              the encoding will encode `size - 7` as a varint next.
            - If encoding is `TAG_ID`, then num_bytes of field name will be used to store tag id.
        - ref tracking: when set to 1, ref tracking will be enabled for this field.
        - nullability: when set to 1, this field can be null.
        - polymorphism: when set to 1, the actual type of field will be the declared field type even the type if
          not `final`.
    - field name: If tag id is set, tag id will be used instead. Otherwise meta string encoding `[length]` and data will
      be written instead.

Related issues

#1556

Does this PR introduce any user-facing change?

• Does this PR introduce any public API change?
• Does this PR introduce any binary protocol compatibility change?

Benchmark

[LiangliangSui]

LGTM