chore(sdk): Remove node id config option

[teogeb]

Removed obsolete NetworkNodeConfig#id config option. The NetworkNodeConfig interface corresponds the ContentDeliveryManagerOptions interface in trackerless-network, and there is no id field in that interface. Therefore the config option doesn't configure anything and is obsolete.

Background

The description of the removed config option was "the Ethereum address of the node". Therefore it is likely that the config option is from pre-trackerless-network era. In that implementation node ids were Ethereum addresses.

Other changes

Fixed config injection problem in OperatorPlugin test. When the "invalid configuration" test case modified the config object returned by formConfig, it modified also the TEST_CONFIG object (because TEST_CONFIG object properties are injected by reference in formConfig). That caused another test in the OperatorPlugin to fail.

• Alternatively we could have done the the cloning in formConfig. But as cloning is needed only in this one test case, maybe better to do it locally.