lol damn
theres gotta be some codebrain that will make a program to do so. i think i saw something like this on armaholic but i didnt read the details.
There is a tool called Yoma Addon Synchronizer that obtains the addons used by the server but
(a) the server needs to be running it to work
(b) the application itself is poorly coded and gives a stupid amount of error messages
(c) it only works before you start the game