Standardize nix directory structure for lts/ghc-9.10.x
requested to merge jonge/horizon-platform:feature/lts/ghc-9.10.x/standardize-nix-directory into lts/ghc-9.10.x
Standardizes nix directory structure using import-tree pattern. Removes configuration/ and develop/ directories, creates modular nix/ directory, uses horizon-ghc compilerConfig, updates to gitlab-ci-omnix 0.5.0.