fix: extend support for r/w feature flags

[IgorEisberg]

Adds support for decoding R/W feature flags from RES_TABLE_FLAGGED and RES_TABLE_FLAG_LIST in ARSC, as well as ResXMLTreeFlagExt blocks in AXML.
New ResXmlPullEventHandler takes care of recording android:featureFlags in all binary XML files, so ResXmlUtils.pullManifestFeatureFlags(manifest) is obsolete.
Everything was written with performance in mind and avoiding costly calls before checking if they're needed.

Extra:

• Make ResStringPool reusable, this cleans unnecessary null checks.
• Stricter equals implementations' class checks.
• Optimized hashCode implementations (Objects.hash is convenient, but implicitly allocates an array each call).
• Tweak YamlReader and YamlWriter to take a Collection over a List for flexibility.

closes: #4217