Extract a PureScript package set for Cardano domain packages

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Task Breakdown:

1. Create a new repository called "purescript-cardano" that will serve supervised package sets with all essential packages needed for development of Cardano-based applications.
2. Update CTL to use the newly introduced package set and make the corresponding adjustments to the documentation: https://github.com/Plutonomicon/cardano-transaction-lib/blob/develop/doc/ctl-as-dependency.md#upgrading-ctl.