Core api concept (#144)

* add input debounce code from old fw

* exampl of input api

* change input API to get/release

* revert input API to read

* pointer instead of instance

* add input API description

* add display API

* rewrite display names

* migrate to valuemanager

* add LED API

* add closing brakets

* add sound api

* fix led api

* basic api

* rename API pages

* change pubsub implementation

* move FURI AC -> flapp, add valuemutex example, add valuemanager implementation

* pubsub usage example

* user led example

* update example

* simplify input

* add composed display

* add SPI/GPIO and CC1101 bus

* change cc1101 api

* spi api and devices

* spi api and devices

* move SPI to page, add GPIO

* not block pin open

* backlight API and more

* add minunit tests

* fix logging

* ignore unexisting time service on embedded targets

* fix warning, issue with printf

* Deprecate furi_open and furi_close (#167)

Rename existing furi_open and furi_close to deprecated version

* add exitcode

* migrate to printf

* indicate test by leds

* add testing description

* rename furi.h

* wip basic api

* add valuemutex, pubsub, split files

* add value expanders

* value mutex realization and tests

* valuemutex test added to makefile

* do not build unimplemented files

* fix build furmware target f2

* redesigned minunit tests to allow testing in separate files

* test file for valuemutex minunit testing

* minunit partial test valuemutex

* local cmsis_os2 mutex bindings

* implement furi open/create, tests

* migrate concurrent_access to ValueMutex

* add spi header

* Lib: add mlib submodule.

Co-authored-by: rusdacent <rusdacentx0x08@gmail.com>
Co-authored-by: DrZlo13 <who.just.the.doctor@gmail.com>

wiki/fw/api/Display-API.md

@@ -0,0 +1,68 @@
+All display operations based on [u8g2](https://github.com/olikraus/u8g2) library.
+
+API available as `ValueComposer`.
+
+Driver call render callback and pass API contains u8g2 functions, instance and fonts:
+
+```C
+typedef struct {
+    u8g2_t* display;
+
+    void (*u8g2_SetFont)(u8g2_t *u8g2, const uint8_t  *font);
+    void (*u8g2_SetDrawColor)(u8g2_t *u8g2, uint8_t color);
+    void (*u8g2_SetFontMode)(u8g2_t *u8g2, uint8_t is_transparent);
+    u8g2_uint_t (*u8g2_DrawStr)(u8g2_t *u8g2, u8g2_uint_t x, u8g2_uint_t y, const char *str);
+
+    Fonts fonts;
+} DisplayApi;
+
+typedef struct {
+    const uint8_t* u8g2_font_6x10_mf;
+} Fonts;
+```
+
+First of all you can open display API instance by calling `open_display`
+
+```C
+/// Get display instance and API
+inline Display* open_display(const char* name) {
+    return (Display*)furi_open(name);
+}
+```
+
+Default display name is `/dev/display`.
+
+For draw something to display you need to register new layer in display composer:
+
+```C
+typedef void (RenderCallback*)(void* ctx, DisplayApi* api);
+
+inline ValueComposerHandle* init_display_composer(
+    Display* api, RenderCallback render, void* ctx, uint32_t layer) {
+    return add_compose_layer(api->composer, (ValueComposerCallback)render, ctx, layer);
+}
+```
+
+And then call `request_compose` every time you need to redraw your image.
+
+## Usage example
+
+```C
+
+void example_render(void* ctx, DisplayApi* api) {
+    api->u8g2_SetFont(api->display, display_api->fonts.u8g2_font_6x10_mf);
+    api->u8g2_SetDrawColor(api->display, 1);
+    api->u8g2_SetFontMode(api->display, 1);
+    api->u8g2_DrawStr(api->display, 2, 12, (char*)ctx); // ctx contains some static text
+}
+
+void u8g2_example(void* p) {
+    Display* display_api = open_display("/dev/display");
+    if(display_api == NULL) return; // display not available, critical error
+
+    ValueComposerHandle display_handler = init_display_composer(
+        display_api, example_render, (void*)"Hello world", UiLayerBelowNotify);
+
+    request_compose(display_handler);
+}
+```