feat: bitwise not unary op

[quinton11]

Patch for #270

Rust uses ! for both logical and bitwise not, where the operand differentiates the use; i.e bool for logical and int variations for bitwise

wgsl however uses ! for logical not and ~ for bitwise not.

The Not op is still kept in tact as it was, handling boolean operands,

Tests now pass for the bitwisenot operation on burn_jit backends. When this is merged, I'll push the changes to bitwise_ops PR here

@laggui

[nathanielsimard]

LGTM