Support serde pickle V4

[WingCode]

Issue #, if available: #18

Description of changes: Using Pickle.jl library to serialise and deserialise pickle objects. Pickle.jl was chosen because:

• It is in native Julia and doesn't require Python call.
• Does only pickling compared to Pandas.jl
• More recent and up to date package compared to alternative PythonIO.jl

Testing done: Locally

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[kshyatt-aws]

Rerunning CI as the failures don't look to be the fault of this PR. I'll mark it approved so UH picks it up.