PocoDoc: search support

[vrabac6]

The PocoDoc did not support integration with FTS5 SQLite database for the purpose of inputting clean content into the database. To enhance its functionality, the following improvements have been implemented:

1. Expanded the writeDescription method by adding an output stream containing clean content.
2. Introduced a new method named writeSearchIndex , responsible for retrieving textual documentation along with links. This method is called within existing methods writeClass , writePackage , and writeNameSpace

[aleks-f]

• Windows CI is failing; this needs update of vs90 project and regeneration of 160 and 170 projects

  D:\a\poco\poco\PocoDoc\src\DocWriter.cpp(29,10): error C1083: Cannot open include 
  file: 'Poco/Data/Session.h': No such file or directory 
  [D:\a\poco\poco\PocoDoc\PocoDoc_vs170.vcxproj]
  Error: Final attempt failed. Child_process exited with error code 1```

• to prevent sanitizer CI failures, either pick these changes or simply merge devel branch
• search support should be a runtime option
  • there should be a command line parameter added to PocoDoc to generate searchable SQLite DB
  • obviously, a precondition is SQLite built with FTS support
  • there should be a way to check at runtime if Data/SQLite supports FTS; only if it does can searchable content be produced (otherwise runtime error if searchable cmd line param was give)

[aleks-f]

• this PR is from devel branch, which was retired 6 months ago; pocoproject/main branch needs to be merged here before this PR is merged
• FTS5 is available only on Android API Level > 24; see with @zaleksandar if this makes it worth keeping the FTS3/4 support alongside FTS5

Overall consolidation of the FTS capabilities is needed (this should probably be a separate issue):

• there are discrepancies/inaccuracies in the build systems:
  • no need for =<path> here
  • this looks like mixing incompatible defines (probably the second one has no effect)
  • apparently, VS projects have FTS3 define hardcoded; on Windows FTS5 should be hardcoded in the projects (regenerated from SQLite.progen, not edited directly)
  • SQLite test has hardcoded FTS3
  • CMake build system should be adjusted to be in accordance with make build, coordinate with @matejk

[vrabac6]

• FTS5 is available only on Android API Level > 24; see with @zaleksandar if this makes it worth keeping the FTS3/4 support alongside FTS5

According to the latest Android documentation, all new apps must target API level 34, and even older apps now target a minimum of API level 31. This makes it effectively impossible for apps to run on API levels lower than 24. Therefore, it should be safe and efficient to always enable FTS5 without needing to maintain support for FTS3/4.

[matejk]

PocoDoc.cmake.patch

Patch to correct CMake files for text search.