Plus fix location of the certificate files in the examples.
Tested with both Ada examples:
```
obj/tls_server_main --psk
obj/tls_client_main 127.0.0.1 --psk
```
- Add comments for the PSK value in the example.
- Add runtime argument for executing the PSK test.
- Warn user that their callback implementation can't be in the SPARK subset.
Tested with:
`wolfSSL/wolfssl-examples/psk/server-psk.c`
after changing `DTLSv1_3_Client_Method` to `DTLSv1_2_Client_Method` to comply with the server example.
The Ada wrapper had an `&` operator for the verification mode. This
effectively caused the verification mode to equal `0`.
The operator has been switched to `or` now, in addition, a getter has
been added to the API. This allows for the test I've added to the server
code to verify that it is being set correctly.
`OPENSSL_ALL` flag added to Ada so that the verify mode getter function
is compiled in.
Fixes#7461
Thanks to @dalybrown for reporting it.
mgrojo
Andrew Hutchings
Daly Brown
Joakim Strandberg
David Garske