rec: fix YAML naming inconsistencies (due to historical reasons)

[omoerbeek]

YAML settings naming is (in general) better than old-style, but there remain inconsistenties in naming conventions. Most important are the fields that correspond to settings originally in Lua config, whoch mostly use CamelCase. Ponder using serde's "alias" feature to allow both the old name and a name matching the snake case convention used elsewheer. The Rust and docs code generator should be adapted to handle this.