Nix in CI: First call using nix takes about an hour

[tateexon]

When we tried to use nix in github actions for this repo we run into an issue where the first nix call always takes about an hour to run. We do not have this issue in the terra repo. I did not manage to find a way to use a cache to solve the problem and so I am not sure how to get around it at this time.

For now we have ripped nix out of any github actions for this repository until a fix can be implemented.
Mostly recently ripped out in #256 in the commit 8509c27

[archseer]

Why wasn't I pinged about this?

This is because shell.nix is my development setup that uses saber-overlay to compile the entire solana toolchain from source. https://github.com/smartcontractkit/chainlink-solana/blob/a3d61f6006f9c16ecd8af969d5d7f9811c977228/flake.nix#L8-L9=

Saber does offer a Cachix (https://www.cachix.org/) cache with binary builds. This is enough to have it pull from cache: https://github.com/saber-hq/install-solana-action/blob/a0a2ac5593e1bd21e2346c0de077b0d8fa92ae93/action.yml#L20-L23=