Document the use of addAllCharsets for Tika extension

[sberyozkin]

Description
As noticed by Guillaume @gsmet, one of the native Tika tests reports an unsupported charset exception

Implementation ideas

TikaProcessor has to produce NativeEnableAllCharsetsBuildItem, possibly optionally

[ppalaga]

We should perhaps recommend setting quarkus.native.add-all-charsets = true in application.properties because it works both in Maven and Gradle.