### What problem were solved in this pull request?

Problem:
add code quality scan.

### What problem were solved in this pull request?

Issue Number: close #178 

Problem:
sysbench is a powerful concurrency test tool and we should use it to
test our program.

### What is changed and how it works?
I create two sysbench lua scripts and a github workflow.

### Other information

### What problem were solved in this pull request?

Issue Number: close #162 

Problem:
当前的observer启动流程和调试方法比较繁琐，必须使用客户端服务端的方式，先启动服务端程序，再使用客户端启动调试

### What is changed and how it works?
observer可以直接启动，不监听tcp或unix socket，直接通过终端/控制台输入命令并执行，极大的方便了调试

### Other information
新的启动方法：
./bin/observer -P cli -f ../etc/observer.ini

### What problem were solved in this pull request?

Problem:
当前生成的github pages不太整洁方便，可以优化一下

### What is changed and how it works?
改用mdbook生成文档，并整理文档目录，调整链接

### What problem were solved in this pull request?

Issue Number: close #188 

Problem:
利用doxygen将代码注释生成文档

### What is changed and how it works?
修改github action，增加doxygen生成文档，并gihtub pages部署发布

### Other information

### What problem were solved in this pull request?

使用doxygen生成代码文档

Problem:
doxygen可以很方便的把代码注释转换成文档，但是当前没有利用这个功能

### What is changed and how it works?
增加了doxyfile，并在github action的workflow中增加了这个功能

### Other information

### What problem were solved in this pull request?

Issue Number: close #169 

Problem:
python测试脚本启动过于复杂；
没有利用python的case测试功能

### What is changed and how it works?
删减掉大部分python测试脚本的参数；
把basic测试用例增加到github action中

### Other information

fix unittest;
add unittest to github action

### What problem were solved in this pull request?

Issue Number: close #176 close #163 

Problem:
单元测试执行失败；
github action 没有单元测试检查

### What problem were solved in this pull request?
github build action adds support for mac system
close #157 
Problem:

### What is changed and how it works?
added ci/cd support for Mac 

Fix problem:
1. the buffer pool and b tree is not thread safe;
2. github/workflow/build does not work

### What is changed and how it works?
1. thread-safe buffer pool
- I use a mutex in buffer pool and take a lock in buffer pool operations
such as allocate frame, dispose frame;
- The frame is locked while updating/reading the content of frame;
- Frame manager take a lock when allocate/free pages.

2. thread-safe b+tree
- Crabing protocol is used to support concurrent

3. github/workflow/build
- update the submodules;
- create a build script and run build.sh in build.yaml

add cmake_prefix_path

add deps prefix

update googletest

update googletest

build googletest