feat: dict based Hyphenation (#305)

## Summary

* Adds (optional) Hyphenation for English, French, German, Russian
languages

## Additional Context

* Included hyphenation dictionaries add approximately 280kb to the flash
usage (German alone takes 200kb)
* Trie encoded dictionaries are adopted from hypher project
(https://github.com/typst/hypher)
* Soft hyphens (and other explicit hyphens) take precedence over
dict-based hyphenation. Overall, the hyphenation rules are quite
aggressive, as I believe it makes more sense on our smaller screen.

---------

Co-authored-by: Dave Allie <dave@daveallie.com>

lib/Epub/Epub/parsers/ContentOpfParser.cpp

@@ -107,6 +107,11 @@ void XMLCALL ContentOpfParser::startElement(void* userData, const XML_Char* name
     return;
   }
 
+  if (self->state == IN_METADATA && strcmp(name, "dc:language") == 0) {
+    self->state = IN_BOOK_LANGUAGE;
+    return;
+  }
+
   if (self->state == IN_PACKAGE && (strcmp(name, "manifest") == 0 || strcmp(name, "opf:manifest") == 0)) {
     self->state = IN_MANIFEST;
     if (!SdMan.openFileForWrite("COF", self->cachePath + itemCacheFile, self->tempItemStore)) {
@@ -266,6 +271,11 @@ void XMLCALL ContentOpfParser::characterData(void* userData, const XML_Char* s,
     self->author.append(s, len);
     return;
   }
+
+  if (self->state == IN_BOOK_LANGUAGE) {
+    self->language.append(s, len);
+    return;
+  }
 }
 
 void XMLCALL ContentOpfParser::endElement(void* userData, const XML_Char* name) {
@@ -300,6 +310,11 @@ void XMLCALL ContentOpfParser::endElement(void* userData, const XML_Char* name)
     return;
   }
 
+  if (self->state == IN_BOOK_LANGUAGE && strcmp(name, "dc:language") == 0) {
+    self->state = IN_METADATA;
+    return;
+  }
+
   if (self->state == IN_METADATA && (strcmp(name, "metadata") == 0 || strcmp(name, "opf:metadata") == 0)) {
     self->state = IN_PACKAGE;
     return;