PSA client-server: generate client- and server-side wrapper code

[gilles-peskine-arm]

Use the PSA wrapper generator library to generate client-side RPC calling code and server-side RPC handling code for the PSA client-server test. Use #8964 as guidance for what RPC functions should look like.

This is for testing, so we don't care about security. However, it would be a plus if the server was actually secure, because then we could adversite it as sample code and not just test code.

This issue is large and should likely be broken down into multiple pull requests. I don't have any particular suggestion on how to break down at this point. Doing a limited subset of functions at a time could be a good way (the wrapper generator has a filter mechanism to only process a subset of functions, and we can gradually make that subset larger).

Prerequisites: #8964, #8961
Can be done before or after #8968