* [posix] POSIX standard implementation for PSE51

- add some posix's interfaces that we haven't before.
- these PR have passed the interface definition test across gcc platfrom;
- have tested base on qemu-a9 and stm32h750-art-pi.

* [newlib] only enable POSIX.1-1990

* update projects

* [kernel][mem] Multiple instances of small memory allocation algorithm

* [kernel][mem] Change small memory management algorithm memory header flag

* [kernel][mem] Fix assertion problem

* [kernel][slab] Multiple instances of slab memory management algorithm

* [kernel][memheap] Remove rt_malloc/rt_free/rt_realloc and other related memory interfaces

* [kernel][mem] Clean up memory space of small memory management objects

* [kernel][kservice] Add memory application interface and thread protection interface

* [kernel][kservice] Fix function return value problem

* [kernel][memheap] Optimize memheaptrace print

* [kernel][memheap] Support best mode

* [kernel][memory] Remove semaphore lock

* [kernel][memheap] Add locked flag

* [kernel][memory] Support malloc memory in interrupt

* [kernel][memheap] Add 'memheapcheck' cmd

* [kernel][mem] Fix failure to request full memory

* [kernel][memheap] Fix compilation warning

* [kernel][mem] Fix mem realloc ASSERT

* [examples][testcases] Add small mem testcase

* [examples][mem_tc] Modify test memory size

* [examples][testcases] Add slab memory management algorithm test case

* [examples][testcases] fix small memory management algorithm test case

* [kernel][memory] Adjusting memory allocation algorithm object definition and interface

* [kernel][memory] Fix compilation warning

* [examples][utest] Fix mem test case

* [examples][utest] fix slab test case

* [utest][testcases] Shorten test time

* [kernel][memory] Formatting code

* [examples][utest] Adjust test run time

* [examples][utest] Formatting code

* [bsp] update all rtconfig.h

CCFLAGS is used by gcc and g++ compiler. So CFLAGS should be used for
gcc to avoid passing gcc flags to g++.

2.Add Kconfig file
3.Delete some unnecessary files and directories

2.Add support for GPIO and UART peripherals
3.Add pin and serial device driver support
4.Put pictures in local folder
5.Modify README file