What type of PR is this?

type-feature
feat-adapt to ob 4.2

What this PR does / why we need it:

this pr makes odc adapt to OceanBase 4.2. we do things in this pr as follow:

1. add schema in generated flashback sql.

the front end will create a new session when using recyclebin so that the observer will flashback the object to the schema where the connection connect to.

To avoid flashbacking a db object to an uncertain schema, we should add schema to the generated sql.

Here is an example:

flashback table `abcd` to before drop rename to `new_name`; -- before
flashback table `abcd` to before drop rename to `schema`.`new_name`; -- after

2. refactor the pojo object's (TraceSpan) structure of full-link trace and convert the field tags's type from List<Map<String, Object>> to List<Object>.

we will get the json string on OceanBase 4.1 when show trace format='json' is executed:

[
    {
        "logs": null,
        "tags": [
           ...
            {
                "log_trace_id": "Y2F170BA2D939-000602A2DA7F897E-0-0"
            }
        ],
        ...

we do the same thing on OceanBase 4.2.1 and get a json string as follow:

[
    {
        "logs": null,
        "tags": [
            [
                ...
                {
                    "log_trace_id": "Y2FB70BA2D939-000608DF99AE2C76-0-0"
                }
            ]
        ],
       ...

as you can see: the structure of the json has been changed, and that is why the full-link trace does not work on OceanBase 4.2.

I change the structure of the pojo object and find another way to avoid this change.

Which issue(s) this PR fixes:

Fixes #94 #506

Special notes for your reviewer:

Additional documentation e.g., usage docs, etc.: