Use libxml2 for DDoc parsing #1214

Job	Run time
Run CodeQL tests	4m 50s
Build on Fedora 39	2m 0s
Run Coverity tests	0s
Build on Fedora 40	2m 24s
Build on macOS for osx	2m 25s
Deploy pages	0s
Build on macOS for ios	1m 24s
Build on Ubuntu 20.04	3m 22s
Build on macOS for iossimulator	2m 20s
Build on Windows (143, x86)	23m 54s
Build on macOS for androidarm	1m 27s
Build on Windows (143, x64)	23m 4s
Build on macOS for androidarm64	1m 35s
Build on Windows (142, x86)	23m 20s
Build on Ubuntu 22.04	3m 6s
Build on macOS for androidx86_64	1m 52s
Build on Ubuntu 23.10	3m 43s
Build on Windows (142, x64)	21m 49s
Build on Ubuntu 24.04	3m 38s
	2h 6m 13s

Provide feedback