[wt] Update to 4.4.0

[RockinRoel]

• Removed obsolete Boost disable autolink patch (Wt no longer uses
  autolinking for recent Boost versions)
• Removed obsolete OpenSSL patch (Wt switched to using the
  standard CMake FindOpenSSL module)
• Listed all Boost dependencies based on which Boost headers Wt uses
• Added optional GraphicsMagick dependency for WRasterImage on non-Windows
• Added libharu dependency for WPdfImage
• Limited Pango dependency to only non-Windows (on Windows DirectWrite
  is used), added a tweak so it finds Harfbuzz and added it to
  Build-Depends
• Added feature switches for Dbo and its backends: Sqlite3, PostgreSQL,
  and MS SQL Server, and for OpenSSL
• Explicitly disabled BUILD_TESTS, ENABLE_FIREBIRD, and ENABLE_QT5
• Reenabled libwttest

[ghost]

All CLA requirements met.

[RockinRoel]

Notes:

• I tried to add support for wtdbomysql by adding a libmariadb dependency, but I'm currently running into some issues getting Wt to use it. This may need some upstream changes.
• There's maybe some dependencies that could be behind feature flags, too. It seemed logical to have feature flags for different Dbo backends, and for OpenSSL. Maybe it also makes sense to do the same for:
  • WRasterImage (needs GraphicsMagick on Linux, can use Direct2D on Windows)
  • advanced font support (needs Pango on Linux, can use DirectWrite on Windows)
  • zlib (compression support in wthttp)
  • WPdfImage (needs libharu)
• I ran into issues building the unixodbc dependency on Fedora, so the sqlserver feature wasn't tested on Linux. I know that normally this works when using the operating system's unixodbc.

[RockinRoel]

I had initially added graphicsmagick as a dependency on Linux, and -DWT_WRASTERIMAGE_IMPLEMENTATION=GraphicsMagick. I thought this was working, but it actually had used my system's GraphicsMagick. I could get it to link properly with the one from vcpkg but it would cause linking difficulty downstream, so I removed it.

[RockinRoel]

I added GraphicsMagick support as an optional feature, using unofficial::graphicsmagick::graphicsmagick.

[BillyONeal]

Thanks for your contribution!