remove unused prototypes folder

prototypes/postgres-1/README.md

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-# Postgres Experiment 1
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-Peter (2022-01-24): Creating this experiment to test basic Course Eval relations in Postgres. See [Notes](../../notes/postgres-1.md) for more details, including intent and design. This is mostly just for me to practice
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prototypes/postgres-rdf-1/README.md

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-# Postgres Resource Description Framework
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-Peter (2022-01-25): This is an experiment to test to what extent Postgres supports RDF relationships or JSON-LD exports and how much we will need to code. See [Notes](../../notes/postgres-rdf-1.md) for more details, including intention and design.
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