OpenSystemsDevelopment / qpdf

…lize type conversions, and improve clarity across multiple modules.

Replaced raw key pointer and length parameters with a `std::string` in `Pl_AES_PDF` and `Pl_RC4` constructors for improved safety and clarity. Updated all usage sites accordingly, reducing reliance on manual memory management and redundant conversions.

…onsolidate `iterate_rc4` logic, and streamline RC4 key processing.

…arrays with `std::string`, and simplify key computation logic.

…ect `substr` calls, and simplify password handling logic.

…ys with `std::string`, and simplify related password handling logic.

…implify padding logic, and streamline password handling across methods.

…ased logic in `setEncryptionMinimumVersion`, and reduce redundancy across `QPDFWriter` methods.

…`, simplify method signatures, and centralize logic in `QPDF::EncryptionData` for improved maintainability.

…ling, and improve maintainability.

…Perms_value_V5` methods; inline their logic into `setV5EncryptionParameters` to simplify encryption data processing.

…dom_string`, improve readability of salts and keys handling, and streamline `compute_Perms_value_V5_clear` logic by returning strings directly.

…std::bitset`, reorganizing related methods, and simplifying access to improve clarity and maintainability.

…irectly access encryption parameters for improved clarity and maintainability.

…, transition `interpretCF` to a class method, and eliminate redundant parameter passing for improved clarity and maintainability.

…rs::initialize` and replacing shared pointers with references for improved clarity and maintainability.

…t parameter passing, and improve maintainability. Change static functions and QPDF methods to EncryptionData methods.

Replace `count` method with iterator-based lookup to improve readability and reduce redundancy. Simplify conditional logic for determining the encryption filter, ensuring the default case remains clear.

Only top-level XMP metadata is supposed to be left unencrypted. All
other metadata is not treated specially.

Except for virtual functions to avoid the need for users to update code.

This improves indentation of long strings. This commit also fixes some
trailing whitespace in ChangeLog.

This reverts commit ff2a78f579ebdd06b417e34260a17dba06e71137, reversing
changes made to 8f54319f7a6514110f4b05cbbf1cb1c9fc8cb6a0.

This reverts commit c648b9a018105a3c30b3e7f3c5f8a058d3ddd92c, reversing
changes made to 12b67a3227df6b6df3a4f5f098e11cce173ff7d5.

Using search and replace.