Fix naming of new prometheus metrics

- Use "CirrusSearch" as a component
- Use non-ambiguous labels, e.g. "cluster" seems to overridden by
  statsd_exporter
- use _seconds and _total suffixes for most timing and counter metrics

Bug: T359033
Change-Id: I9653fc43f0b05b5b90c8d60d1d086544823499c8

• includes/DataSender.php[diff]
• includes/ElasticsearchIntermediary.php[diff]
• includes/Job/ElasticaWrite.php[diff]
• includes/Query/DeepcatFeature.php[diff]
• includes/Sanity/Checker.php[diff]
• includes/Search/FullTextResultsType.php[diff]
• includes/Searcher.php[diff]
• includes/Util.php[diff]
• tests/phpunit/integration/Job/ElasticaWriteTest.php[diff]