Increase robustness of `XMLDocument` parser

Слиты xottab-duty запросил слияние github/fork/AMS21/parser/xml_document в dev

Created by: AMS21

  • Initialize m_bIgnoreMissingEndTagError
  • Pass down bool fatal to ParseFile. Previously we would still hit assertions for invalid #includes with fatal set to false
  • Fix potential use of nullptr when strstr returns nullptr
  • Introduce a non failing variant of r_string called try_r_string
  • Fix various problems with the handling of #include, remove not needed string copy and give feedback on invalid things instead of silently ignoring problems.
  • Fix an infinite loop in tinyxml when parsing an invalid UTF-8 sequence
  • Fix infinite recursion or cyclic includes causing a stack overflow