Keep only the generated files needed for tests. Place generated
intermediaries in `tests/certs/gen` where they are ignored by git. No
longer generated `*.dhp` files.
Have a shorter naming scheme: `test-ca` instead of `EdelCurlRoot-ca` and
`test-localhost` instead of `Server-localhost-sv`, etc.
Remove the `stunnel` certificate as it was nearly a duplicate of
`test-localhost`.
No longer copy a generated certificates to `tests/stunnel.pem`. Let test
server default to `certs/test-localhost.pem` instead.
Closes#16593
The threee tags `<name>`, `</name>` and `<command>` were frequently used
with a leading space that this removes. The reason this habbit is so
widespread in testcases is probably that they have been copy and pasted.
Hence, fixing them all now might curb this practice from now on.
Closes#12028
