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

Merge Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your pull request.

General

• I have read the CONTRIBUTING doc
• I used the commit message format described in CONTRIBUTING
• I have updated any necessary documentation, including READMEs and API docs (if appropriate)

Tests

• I have installed and run git secrets to make sure I did not commit any sensitive information (passwords or credentials)
• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have checked that my tests are not configured for a specific region or account (if appropriate)

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[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.

[kshyatt-aws]

Wait to merge until CI passes, or merge into a feature branch