lcd: simplify lcd example

Move the lcd example files out of the folder spi_master, and refactor
the codes with esp_lcd driver. Add image rotation function to the
example.

examples/peripherals/spi_master/lcd/main/decode_image.h

@@ -1,22 +0,0 @@
-/*
-   This example code is in the Public Domain (or CC0 licensed, at your option.)
-
-   Unless required by applicable law or agreed to in writing, this
-   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
-   CONDITIONS OF ANY KIND, either express or implied.
-*/
-
-#pragma once
-#include <stdint.h>
-#include "esp_err.h"
-
-/**
- * @brief Decode the jpeg ``image.jpg`` embedded into the program file into pixel data.
- *
- * @param pixels A pointer to a pointer for an array of rows, which themselves are an array of pixels.
- *        Effectively, you can get the pixel data by doing ``decode_image(&myPixels); pixelval=myPixels[ypos][xpos];``
- * @return - ESP_ERR_NOT_SUPPORTED if image is malformed or a progressive jpeg file
- *         - ESP_ERR_NO_MEM if out of memory
- *         - ESP_OK on succesful decode
- */
-esp_err_t decode_image(uint16_t ***pixels);