Rename random decimal to random float (#10320)

# Description
Similar to #9979

# User-Facing Changes
`random decimal` will now raise a warning and can be removed in an
upcoming release.

New command is named `random float`

# Tests + Formatting
Tests updated and improved.

crates/nu-command/tests/commands/random/mod.rs

@@ -1,7 +1,7 @@
 mod bool;
 mod chars;
-mod decimal;
 mod dice;
+mod float;
 mod integer;
 #[cfg(feature = "uuid_crate")]
 mod uuid;