Revert "Merge branch 'feature-NXCALS-3831-expand-search-for-context-variables' into 'develop'"

Reason why we need to revert:

There is a time processing issue (after the latest changes introduced) that is causing 3 related integration test cases to fail.

The above issue has already affected our TEST and STAGE JenkinsCI pipelines.

The exceptions that we get on integration tests execution is the following:

java.time.format.DateTimeParseException: Text '2009-01-01T00:00:00.000Z' could not be parsed at index 10
	at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949)
	at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
	at java.time.LocalDateTime.parse(LocalDateTime.java:492)
	at cern.nxcals.api.utils.TimeUtils.getInstantFromString(TimeUtils.java:90)
	at cern.nxcals.api.extraction.data.builders.fluent.TimeStartStage.startTime(TimeStartStage.java:23)
	at cern.nxcals.api.backport.client.service.MetaDataServiceImpl.getVectorElementsInTimeWindow(MetaDataServiceImpl.java:262)
	at cern.nxcals.api.backport.client.service.MetaDataServiceImpl.getVectorElements(MetaDataServiceImpl.java:233)
	at cern.nxcals.integrationtests.backport.BackportTimeseriesDataServiceTest.shoulGetVectorElements(BackportTimeseriesDataServiceTest.java:773)
... truncated output for simplisity

@acc-logging-team - please have a look for approval.

Please describe the merge request here.