Decimals.jl support

[johnzl-777]

Describe the feature you'd like
The current Braket IR uses Dec128 from DecFP to represent the Decimal type but this relies on an external Intel library. It would be nice if Decimals.jl support could be added as a Julia-native option for the Decimal type.

How would this feature be used? Please describe.
There are plans for the Bloqade.jl schema to use Decimals.jl. If the Braket IR supported Decimals.jl it would make future IR conversions much easier 😃

Credit to @Roger-luo and @weinbe58 for the idea

[kshyatt-aws]

The problem for us is that Decimals.jl seems pretty abandoned (last tagged version in 2020) and the Decimal type doesn't support hashing, for example. Is the reliance on an Intel library the main blocker for you? Would it be enough to modify Braket.jl to allow constructing the higher-level constructs using Decimal even if internally they use Dec128?

[weinbe58]

No, its not a blocker for us, It would be nice to have a pure Julia implementation to support the most platforms.

I think in the Long term a redesign of the IR will hopefully make this need for Dec128 obsolete, more details to come hopefully.