Set scope highlight by `ibl.setup_buffer`

### Problem

rainbow-delimiters could be disabled for specific buffers, it would be better if indent-blankine's scope highlight is buffer-scoped so that we can only apply rainbow-delimiters' highlights to the buffers it enabled, and keep `IblScope` in the buffer rainbow-delimiters does not enabled.

### Expected behavior

scope highlight is buffer-scoped and could be set by `ibl.setup_buffer`