Documentation: fixed outdated naming (#1518)

* Documentation: fixed outdated naming: changed outdated naming in assets/dolphin/ReadMe. `essential -> blocking`
* Updated naming convencion in assets/ReadMe file and assets/dolphin/ReadMe file

Co-authored-by: あく <alleteam@gmail.com>

assets/ReadMe.md

@@ -38,10 +38,10 @@ Good starting point: https://docs.unrealengine.com/4.27/en-US/ProductionPipeline
 Don't include assets that you are not using, compiler is not going to strip unused assets.
 
 # Structure
-
-- `compiled`            - Output folder for compiled assets.
-- `dolphin`             - Dolphin game assets sources. Goes to `compiled` and `resources` folders.
-- `icons`               - Icons sources. Goes to `compiled` folder.
-- `protobuf`            - Protobuf sources. Goes to `compiled` folder.
+- `compiled`            - Output folder made for compiled assets, after building project, in `build` directory.
+- `dolphin`             - Dolphin game assets sources. Goes to `compiled` and `resources` folders in `build` directory.
+- `icons`               - Icons sources. Goes to `compiled` folder in `build` directory.
+- `protobuf`            - Protobuf sources. Goes to `compiled` folder in `build` directory.
 - `resources`           - Assets that is going to be provisioned to SD card.
-- `slideshow`           - One-time slideshows for desktop 
+- `slideshow`           - One-time slideshows for desktop
+- `unit_tests`          - Some pre-defined signals for testing purposes.

assets/dolphin/ReadMe.md

@@ -2,7 +2,7 @@
 
 Dolphin assets are split into 3 parts:
 
-- essential - Essential animations that are used for blocking system notifications. They are packed to `assets_dolphin_essential.[h,c]`.
+- blocking - Essential animations that are used for blocking system notifications. They are packed to `assets_dolphin_blocking.[h,c]`.
 - internal  - Internal animations that are used for idle dolphin animation. Converted to `assets_dolphin_internal.[h,c]`.
 - external  - External animations that are used for idle dolphin animation. Packed to resource folder and placed on SD card.
 
@@ -10,7 +10,7 @@ Dolphin assets are split into 3 parts:
 
 - `manifest.txt` - contains animations enumeration that is used for random animation selection. Starting point for Dolphin.
 - `meta.txt`     - contains data that describes how animation is drawn.
-- `frame_X.bm`   - Flipper Compressed Bitmap.
+- `frame_X.png`  - animation frame.
 
 ## File manifest.txt