Remove flash_read_bulk(), refactor website and execute_config().

flash_read_bulk() is kind of a printf function. But did not work as well.
flash_read_bulk() was used in the http generation so this needed to be changed as well.

For the website we decided that we are going to use CSR(Client Side Rendering).
So every HTML and JS files are now static.
Variables are fetched via json calls and output is render on the client side.
Also usefull for the future when we want a REST like API.

execute_config() was also using flash_read_bulk().
This have been replaced with flash_read_bulk() and parsing the flash_buf buffer.

rtl837x_flash.h

@@ -10,5 +10,4 @@ void flash_read_security(uint32_t addr, uint8_t len);
 void flash_sector_erase(uint32_t addr);
 void flash_read_bulk(__xdata uint8_t *dst);
 void flash_write_bytes(__xdata uint8_t *ptr);
-void flash_find_mark( __code uint8_t *mark, __xdata uint16_t len);
 #endif