refactor: new BinaryXmlResourceParser, ResXmlSerializer and more

[IgorEisberg]

Describing this PR fully is like writing a novel, so I'll sum up the main changes. Most of the code has comments and notes anyway, especially on sensitive/confusing parts.

• A new BinaryXmlResourceParser fully powered by ResChunkPullParser. Some obfuscated APKs that couldn't be decoded properly are now easily decoded.
• ResXmlSerializer replaces MXSerializer. It's a stripped-down and customized version of KXmlSerializer (used in AOSP) that's made specifically for safely writing resource XML files.
• ResStringEncoder (accompanied by brut.util.TextUtils) handles most of the encoding and escaping of strings. The value of ResString can now be StyledString as well, and ResStringEncoder handles the spans properly according to StyledString rules. The encoder uses the same StringBuilder through the whole process without allocating any substrings, much lower overhead than prior methods.
• literals.xml has been expanded to demonstrate the new capabilities of the smart escaping algorithm.
• Added --ignore-raw-values advanced option. The only APK that uses the --keep-raw-values aapt2 option that I know of is CarrierConfig.apk that preserves MCC/MNC raw values. Not used much in normal production.
• Cleared up a lot of boilerplate code.
• android.* code removed, most of it was unused. The used parts merged into code where they are relevant. This will prevent breaking conflicts for people who use Apktool as a library along with AOSP code.
• Silenced some warnings about uninteresting stuff like dummy chunks or padding added by obfuscators.

Tested on large scale. Let me know if there are any questions.

[iBotPeaches]

Nice work. Debian would love to hear that android.content.* is removed