Optimize number of max processes used for computing and limit number of thread running load_data_in_thread()

For max processes used for computing, we need to make sure every summary directory has a process to load data. We also should not use too many processes to avoid system problems (eg. out of memory). So we calc the max processes cnt in _calc_default_max_processes_cnt

For _load_data_in_thread_wrapper, because self._load_data_in_thread() will create process pool when loading files, we can not afford to run multiple self._load_data_in_thread() simultaneously. So we use a lock to make sure that only one self._load_data_in_thread() is running.

Merge pull request !439 from 冯学峰/myMaster01

Merge pull request !437 from wangshuide/wsd_multiple_processes_for_file_parsing

1. To accelerate summary file parsing, multiple processes are used. As the first step to mindinsight parsing performance optimization, we only made changes to _load_single_file function.

2. This PR will imporve summary parsing throughput dramatically (about cpu_count times)

3. Changes are mainly about _load_single_file function

In the future, a more global concurrent computing framework is needed for mindinsight. See the gitee wiki doc for details.

Merge pull request !438 from 冯学峰/myMaster01

Merge pull request !436 from 冯学峰/myMaster01

Merge pull request !434 from 黄伟锋/master

Merge pull request !435 from 夏易凡/0710master

dispalyed in the table area
UI fix an issue where the table hearder could not be restored after
being dragged
UI fix an issue where the tensor page is dispalyed when you drag a table
on the dashboard page

Merge pull request !431 from 冯学峰/myhardware01

Merge pull request !430 from 黄伟锋/master

Merge pull request !433 from wangshuide/fix_ci

Merge pull request !432 from 夏易凡/0710master

1.fix an issue where the table would be displayed incorrectly when an
  error message was displayed in full screen
2.the mouse position in histogram mode is optimized
3.fix an issue where the step was displayed incorrectly when slider move
  fast

Merge pull request !426 from 黄伟锋/master

Merge pull request !429 from yelihua/dev_profiler

Merge pull request !420 from 夏易凡/0710master

!422 The model traceability judgment includes the use of the includes method, which results in the index not being obtained
Merge pull request !422 from 秦君艳/master

Merge pull request !425 from liangyongxiong/rectify-readme-hyperlink

Merge pull request !424 from zhangyunshu/zys_timeline_fixed_filenotfounderror

Merge pull request !411 from maning202007/master

Merge pull request !419 from 秦君艳/master

Merge pull request !417 from 黄伟锋/myMaster

Merge pull request !415 from 夏易凡/0710master

1.The table drawing performance is optimized when the table is automatically refreshed.
2.Fixed some self-verification issues.
3.Related error codes are added.

Merge pull request !416 from 王卫宁/wwn2