The problem with bots is those are too game logic specific, so anyone will hardly make a bot that will be easy to move from one game into another.
The only way I can think of it, is by creating a "base schema" for the bot movement state (I mean using specific properties calle "x", "y", "z"), and then run a small method that will make changes on those properties (this will be move the bot).
For example, using intervals you can increase/decrese the x, y, z values for some specific time, then do a random to pick another property and do it again.
Now: my point is, that will get totally invalid if you have a physics engine implemented where you need to change the bot speed, or deal with gravity, friction, etc.
The easy part will be you can treat bots as any other players, so you shouldn't need to change anything on the client to make these work, just add the entities on the server and make them move randomly.
Hope this helps!