Fileman default open and Screenshot viewer (#1102)

* WIP expensive way

* Add default file handling to fileman

* Remove screenshot_reader and tests

* Read data in chunks

* Format

* Fix error text position

* PR feedback

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Co-authored-by: kallanreed <kallanreed@outlook.com>

firmware/application/file.hpp

@@ -371,6 +371,7 @@ class File {
     Result<Size> read(void* data, const Size bytes_to_read);
     Result<Size> write(const void* data, Size bytes_to_write);
 
+    Offset tell() const;
     Result<Offset> seek(uint64_t Offset);
     Result<Offset> truncate();
     // Timestamp created_date() const;