no-jira: fix the error in perf500 test in PropertyTest, remove reference to log4j logger in tests, remove duplicate closeSession in @after

FXOLAT-207: fix some erros in Spring configuration specific to tests, make the Grizzly start only once to prevent memory leaks, update pom to use the resources in src/test/java..., fix some path in olat.local.properties (test specific)

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branch : bps