chore(neovim): touch-ups

- Move ollama plugin out of user.lua, as that file has basically just UI
configuration
- Remove zen astrocommunity configuration and enable snacks.nvim's zen
- Remove unused community plugins
- Configure catppuccin/nvim's integrations, adding snacks.nvim and
blink.cmp while removing notify, telescope and nvim-cmp

modules/neovim/lua/plugins/snacks-nvim.lua

@@ -0,0 +1,7 @@
+--- @type LazySpec
+return {
+  "folke/snacks.nvim",
+  opts = function(_, opts)
+    opts.zen = { enabled = true }
+  end,
+}