update the trace model in database

[llmhyy]

Trace has isMultithread removed, and has isMain and threadName added;

TraceNode has timestamp added.

[SongXueZhi]

e03981795c78c5e0c76406476203b712b9c9ed50 a520a8f545b386ae9f3c63eb5ccc2e1d7a65eee4 The two commits modified the database table structure and related reading and writing code, please review and close this issue

[SongXueZhi]

a520a8f545b386ae9f3c63eb5ccc2e1d7a65eee4 Note that all the field types have been modified to text and integer, and the primary key still uses the UUID of the text type. For more information about the reason, please see: http://note.youdao.com/noteshare?id=9fc6a763db5b080a38f1c1fb5eb8b641