Fix Botan 3 build (#9388)
* SymmetricCipher: Fix Botan 3 build
Botan commit 819cf8fe6278a19b8266f449228f02fc28a4f784 changed Botan::Cipher_Dir to be a scoped enumeration, so the users must be adapted.
This change causes no issues with Botan 2 because normal enumeration values can also be referred to the same way scoped enumeration values are accessed.
* Auto detect Botan3
* AsyncTask: Do not use `std::result_of`
`std::result_of` was deprecated in C++17 and then it was subsequently removed in C++20. One could use `std::invoke_result_t`, but let Qt figure out the return type instead.
* Collapse Botan2 and Botan3 find package into one
* Update COPYING
* Fixes#5295
* Introduce a callback approach to AsyncTask instead of entering multiple QEventLoop in the stack. This has additional benefits including not returning to the original stack location and potentially operating on deleted objects (use after free).
Many lines were not conformant with the project's formatting rules.
This patch should fix all formatting and whitespace issues in the code
base.
A clang-format directive was put around the connect() calls containing
SIGNALs and SLOTs whose signatures would be denormalized because of the
formatting rules.
