New project token support

[VasilyStrelyaev]

fixes https://github.com/DevExpress/testcafe-dashboard/issues/1094

• In validateSettings, the authentication token is now decoded similar to the Dashboard side. An error is thrown if the token is neither a valid legacy nor a valid new token. Here I should note that if you present a new token to an old validation function (i.e., specify a new token to an old testcafe-reporter-dashboard version), validation will fail. That's intended, because an old reporter won't be able to request a new Dashboard's API handler to verify the tokenId.
• I use a newly introduced reporter.init method to request the Dashboard's verifyReporter API handler to verify the token. If the response is negative (that is, the tokenId is not valid), the init method throws an exception.
• The exception is a special type InitializationError to pass through our own error catching in assignReporterMethods and inform TestCafe that the reporter is not able to initialize (TestCafe should stop the test run).

[VasilyStrelyaev]

Backward compatibility note:

To sum up: you can use legacy tokens with any toolset. New tokens require up-to-date tools.

Since we won't display legacy tokens anywhere when we release a version with new tokens, users will be forced to upgrade TestCafe + Reporter if they lose their legacy token (whenever they keep it).