Implement User Defined Functions for Local CLI Executor (#2102)

* Implement user defined functions feature for local cli exec, add docs

* add tests, update docs

* fixes

* fix test

* add pandas test dep

* install test

* provide template as func

* formatting

* undo change

* address comments

* add test deps

* formatting

* test only in 1 env

* formatting

* remove test for local only

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Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>