Adapting to new haskell-lsp

[alanz]

• It uses rope-utf16-splay instead of yi-rope
• Moving some functionality and types from haskell-ide-engine to haskell-lsp, to benefit other LSP servers based on it
• It is a step toward bringing in the hie-bios being worked on by @mpickering

This is WIP pending merges of

• Rope util funcs lsp#164
• https://github.com/alanz/lsp-test/tree/az-hie-bios

[alanz]

I am planning on merging this when CI passes, so I can fix haskell/lsp#162 before publishing a new haskell-lsp.