The Keyword you are searching is :
electric Door Catch
Here are some Search-Results (but from my country) :
Google[
^]
But you should realize :
This part is only Hardware. To make it work you also need a matching Power Supply, the Installation and from your PI an Output which switches it. This Output must be able to deliver the needed Current.
Last not least someone must do the Installation for you ... and this one should know what he is doing there ...