Add default TokenIdentifier for PrimaryKeySessionAuthenticator #809

Job	Run time
cs-stan / Coding Standard & Static Analysis	30s
testsuite / testsuite-linux (8.2, highest, false)	34s
testsuite / testsuite-linux (8.5, highest, false)	1m 26s
testsuite / testsuite-linux (8.2, lowest, false)	39s
testsuite / testsuite-linux (8.3, highest, false)	34s
testsuite / testsuite-linux (8.4, highest, false)	1m 21s
	5m 4s

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