fix: Set param from config

[delphisharp]

Dear ALL：

目前模型的默认模式名是通过环境变量传递的，我认为实现方法不够python。 所以，我实现了另一种解决方法。

修改 sqllineage/config.py 实现配置项的读取和写入， 读取方法保持和已有方法兼容。 修改 sqllineage/core/models.py 的Schema 类，在每次初始化的时候动态读取配置 修改 sqllineage/runner.py的init方法，传入变量，并在 SQLLineageConfig 赋值 请大家提出意见，谢谢 Currently the default schema name of the model is passed through environment variables, and I think the implementation method is not python enough. So, I implemented another workaround.

Modify sqllineage/config.py to implement reading and writing of configuration items. The reading method remains compatible with the existing method. Modify the Schema class of sqllineage/core/models.py and dynamically read the configuration every time it is initialized. Modify the init method of sqllineage/runner.py, pass in variables, and assign values in SQLLineageConfig Please give your opinions, thank you

重新建立分支并提交 Re-branch and submit

first step to solve #536

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.51%. Comparing base (c23d38d) to head (33bf65e). Report is 3 commits behind head on master.

:exclamation: Current head 33bf65e differs from pull request most recent head 687f7da. Consider uploading reports for the commit 687f7da to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #553   +/-   ##
=======================================
  Coverage   99.50%   99.51%           
=======================================
  Files          41       41           
  Lines        2219     2251   +32     
=======================================
+ Hits         2208     2240   +32     
  Misses         11       11           

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[reata]

Do we have all the codes in this new branch? I remember we need to change the Schema model in #545

[delphisharp]

Do we have all the codes in this new branch? I remember we need to change the Schema model in #545

Sorry, there were some problems when my local branch was synchronized from upstream changes of the master. So a new branch was reopened.

[reata]

What's the difference between this and #555 ? Do they jointly solve #536 and is there any dependency, like I need to merge this PR first and then #555?