Feature Request: Telescope pickers for upstream and downstream models

[Doekeb]

Would love to see two more telescope pickers: one for models downstream from the current, and one for models upstream. I guess picker performance #18 is a bit of a prerequisite

[cmpadden]

@Doekeb -

I took a stab at implementing this using the --select=current_model+ and --select=+current_model syntax.

https://github.com/PedramNavid/dbtpal/pull/35

Open to suggestions on the implementation and naming. Here is how I currently configure it:

vim.keymap.set("n", "<leader>dm", require("dbtpal.telescope").dbt_picker)
vim.keymap.set("n", "<leader>dd", require("dbtpal.telescope").dbt_picker_downstream)
vim.keymap.set("n", "<leader>du", require("dbtpal.telescope").dbt_picker_upstream)