feat: Take screenshots (#759)

## Summary

* **What is the goal of this PR?** Implements a take-screenshot feature
* **What changes are included?**

- Quick press Power button and Down button at the same time to take a
screenshot
- Screenshots are saved in `screenshots` folder

## Additional Context

- Currently it does not use the device orientation.

---

Example screenshots:


![screenshot-6771.bmp](https://github.com/user-attachments/files/25157071/screenshot-6771.bmp)

[screenshot-6771.bmp](https://github.com/user-attachments/files/25157071/screenshot-6771.bmp)


![screenshot-14158.bmp](https://github.com/user-attachments/files/25157073/screenshot-14158.bmp)

[screenshot-14158.bmp](https://github.com/user-attachments/files/25157073/screenshot-14158.bmp)


### AI Usage

Did you use AI tools to help write this code? _** YES

---------

Co-authored-by: Eliz Kilic <elizk@google.com>
Co-authored-by: Xuan Son Nguyen <son@huggingface.co>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Arthur Tazhitdinov <lisnake@gmail.com>

lib/I18n/I18nKeys.h

@@ -355,6 +355,7 @@ enum class StrId : uint16_t {
   STR_BOOK_S_STYLE,
   STR_EMBEDDED_STYLE,
   STR_OPDS_SERVER_URL,
+  STR_SCREENSHOT_BUTTON,
   // Sentinel - must be last
   _COUNT
 };

lib/I18n/translations/czech.yaml

@@ -317,3 +317,4 @@ STR_UPLOAD: "Nahrát"
 STR_BOOK_S_STYLE: "Styl knihy"
 STR_EMBEDDED_STYLE: "Vložený styl"
 STR_OPDS_SERVER_URL: "URL serveru OPDS"
+STR_SCREENSHOT_BUTTON: "Udělat snímek obrazovky"

lib/I18n/translations/english.yaml

@@ -317,3 +317,4 @@ STR_UPLOAD: "Upload"
 STR_BOOK_S_STYLE: "Book's Style"
 STR_EMBEDDED_STYLE: "Embedded Style"
 STR_OPDS_SERVER_URL: "OPDS Server URL"
+STR_SCREENSHOT_BUTTON: "Take screenshot"

lib/I18n/translations/french.yaml

@@ -317,3 +317,4 @@ STR_UPLOAD: "Envoi"
 STR_BOOK_S_STYLE: "Style du livre"
 STR_EMBEDDED_STYLE: "Style intégré"
 STR_OPDS_SERVER_URL: "URL du serveur OPDS"
+STR_SCREENSHOT_BUTTON: "Prendre une capture d'écran"

lib/I18n/translations/german.yaml

@@ -317,3 +317,4 @@ STR_UPLOAD: "Hochladen"
 STR_BOOK_S_STYLE: "Buch-Stil"
 STR_EMBEDDED_STYLE: "Eingebetteter Stil"
 STR_OPDS_SERVER_URL: "OPDS-Server-URL"
+STR_SCREENSHOT_BUTTON: "Screenshot aufnehmen"

lib/I18n/translations/portuguese.yaml

@@ -317,3 +317,4 @@ STR_UPLOAD: "Enviar"
 STR_BOOK_S_STYLE: "Estilo do livro"
 STR_EMBEDDED_STYLE: "Estilo embutido"
 STR_OPDS_SERVER_URL: "URL do servidor OPDS"
+STR_SCREENSHOT_BUTTON: "Capturar tela"

lib/I18n/translations/russian.yaml

@@ -317,3 +317,4 @@ STR_UPLOAD: "Отправить"
 STR_BOOK_S_STYLE: "Стиль книги"
 STR_EMBEDDED_STYLE: "Встроенный стиль"
 STR_OPDS_SERVER_URL: "URL OPDS сервера"
+STR_SCREENSHOT_BUTTON: "Сделать снимок экрана"

lib/I18n/translations/spanish.yaml

@@ -317,3 +317,4 @@ STR_UPLOAD: "Subir"
 STR_BOOK_S_STYLE: "Estilo del libro"
 STR_EMBEDDED_STYLE: "Estilo integrado"
 STR_OPDS_SERVER_URL: "URL del servidor OPDS"
+STR_SCREENSHOT_BUTTON: "Tomar captura de pantalla"

lib/I18n/translations/swedish.yaml

@@ -317,3 +317,4 @@ STR_UPLOAD: "Uppladdning"
 STR_BOOK_S_STYLE: "Bokstil"
 STR_EMBEDDED_STYLE: "Inbäddad stil"
 STR_OPDS_SERVER_URL: "OPDS-serveradress"
+STR_SCREENSHOT_BUTTON: "Ta en skärmdump"