String asApiKey() {
            return String.join(API_KEY_SEPARATOR, type, hash, randomCode);
        }
For a key like
<pre>{@code
sak_50910c4ef3_Lz3mnbGYS14fn14LWZFvCn2wPD2bB.....yFimeDifW2FZmj8TixAAgGMM1BeJLpT5cN5ztTuNK3SZ8JZogL
}</pre>
return
<pre>{@code
sak_50910c4ef3_
}</pre>
This is to allow a user to identify their key. This prefix part may not be unique as it is only 7 chars of the
hash, however it probably is, so is good enough.
stroom-security/stroom-security-impl/src/main/java/stroom/security/impl/apikey/ApiKeyGenerator.java