Update OrekitInternalError class and enumerate OrekitMessages.INTERNAL_ERROR message
In OrekitInternalError, the contact mail orekit-developers@orekit.org is no longer valid.
As a consequence, the enumerate OrekitMessages.INTERNAL_ERROR message "internal error, contact maintenance at {0}" must also be changed into a message like "Create issue at {0}" where part {0} of the message is the issues URL: https://gitlab.orekit.org/orekit/orekit/issues.
The associated translations must also evolve (under src/main/resources/assets/org/orekit/localization).