Enable jsonrpc when merge is enabled

[asdacap]

Enable JsonRpc if disabled and if merge is enabled.

Changes:

• Enable jsonrpc config and disable url without engine api if merge is enabled and jsonrpc is disabled.
• Throw an exception if no engine rpc module is configured at all.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Other (please describe):

Testing

• Verified engine api endpoint is open when json rpc config is enabled.
• Verified exception is thrown when no url with engine api is configured.

Further comments (optional

• We can also, don't update the config and just throw validation error.
• We can also, replace the whole config with a default merge jsonrpc config.

[LukaszRozmej]

maybe more of InvalidOperationException or something else?

[asdacap]

Ok