Switch to new lazy-based config

Still a bit WIP. Gradually adding back old plugins and config from old config.

lua/plugins/neotest.lua

@@ -1,17 +0,0 @@
-local neotest = require('neotest')
-neotest.setup({
-  adapters = {
-    require('neotest-rust'),
-  },
-})
-
-vim.keymap.set("n", "<leader>t", function() neotest.run.run() end, { desc = "Run neo[T]ests under cursor"})
-vim.keymap.set("n", "<leader>tf", function() neotest.run.run(vim.fn.expand('%')) end, { desc = "Run neo[T]ests in current file" })
-vim.keymap.set("n", "<leader>tt", function() neotest.run.run({ strategy = 'dap' }) end, { desc = "Run neo[T]ests in DAP debugging mode" })
-vim.keymap.set("n", "<leader>ta", function() neotest.run.attach() end, { desc = "[A]ttach to neo[T]est process" })
-vim.keymap.set("n", "<leader>to", function() neotest.output.open({ enter = true }) end, { desc = "[O]pen neo[T]ests summary window" })
-vim.keymap.set("n", "<leader>ts", function() neotest.summary.toggle() end, { desc = "Toggle neo[T]est [S]ummary window"})
-
-vim.diagnostic.config({
-  neotest = true,
-}, vim.api.nvim_create_namespace('neotest'))