feat: basic nvim-dap setup

nvim/lua/user/file_exists.lua

@@ -0,0 +1,8 @@
+local F = {}
+
+function F.file_exists(name)
+   local f=io.open(name,"r")
+   if f~=nil then io.close(f) return true else return false end
+end
+
+return F