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

---------

Co-authored-by: Jonathan White <support@dmapps.us>

COPYING

@@ -27,28 +27,24 @@ Copyright: 2010-2012, Felix Geyer <debfx@fobos.de>
            2000-2008, Tom Sato <VEF00200@nifty.ne.jp>
            2013, Laszlo Papp <lpapp@kde.org>
            2013, David Faure <faure@kde.org>
-           2016-2020, KeePassXC Team <team@keepassxc.org>
+           2016-2023, KeePassXC Team <team@keepassxc.org>
 License: GPL-2 or GPL-3
 
 Comment: The "KeePassXC Team" in every copyright notice is formed by the following people:
            - droidmonkey
            - phoerious
-           - TheZ3ro <io@thezero.org>
+           - varjolintu
+           - hifi
            - louib
-           - weslly
          Every other contributor is listed on https://github.com/keepassxreboot/keepassxc/graphs/contributors
 
 Files: cmake/CodeCoverage.cmake
 Copyright: 2012 - 2015, Lars Bilke
 License: BSD-3-clause
 
-Files: cmake/FindYubiKey.cmake
-Copyright: 2014 Kyle Manna <kyle@kylemanna.com>
-License: GPL-2 or GPL-3
-
-Files: cmake/FindBotan2.cmake
-Copyright: 2018 Ribose Inc.
-License: BSD-2-clause
+Files: cmake/FindBotan.cmake
+Copyright: none
+License: LGPL-2.1
 
 Files: cmake/GenerateProductVersion.cmake
 Copyright: 2015 halex2005 <akharlov@gmail.com>