export less prefixes with turtle

[KonradHoeffner]

Either define less prefixes in the configuration file or export only used prefixes with Turtle.
The prefixes could also be taken from the input Turtle file.

[KonradHoeffner]

See also pchampin/sophia_rs#113 and oxigraph/rio#42.
Investigate, if https://github.com/oxigraph/rio/releases/tag/v0.7.1 helps.

[KonradHoeffner]

As there seems to be no option in https://docs.rs/sophia_turtle/latest/sophia_turtle/serializer/turtle/struct.TurtleConfig.html to export only used prefixes, this seems not the right place to implement it in RickView for the very limited estimated benefit, marking it as wontfix.

If anyone really needs this or has a single to very-few line of code implementation for this, feel free to reopen this issue. A PR would be very welcome as well :-).