Implement Bigtable timeout settings, with metrics and logs (#733 + #763)

PR's included in this release

• Implement Bigtable timeouts&retry settings #733
• per x-client-id timeout logging & metrics #763

NOTE that the Bigtable config is unchanged - there should be absolutely no observable behavioural changes w.r.t. Bigtable timeouts and retries.

2.3.17

• Revert input variable to 'source' (#758)
• improved Mandatory ID Filter to return info upon rejection (#751)

2.3.16

• Remove legacy source input, move distribution type out of request input (#749)
• Remove static import statement that keep failing sporadically (#747)

Release 2.3.15: Enforce Mandatory Client ID (Github Issue #704) (#727)

this is the implementation of x-client-id header enforcement in Heroic (as opposed to the just-reverted Envoy implementation)

Release 2.3.14

• Introduce support for RotatingIndexMapping to limit the number of elasticsearch metadata indices read based upon the range of a heroic query. If the newly introduced config flag is set to true, the number of read indices is dynamically determined based upon the rotation interval and the range of the query. (#746)

Closes #745.

Release 2.3.13

• Add a simple group combiners and additional IT tests. (#744)

Release 2.3.12

• The interval variable in RotatingIndexMapping is now respected if present in configuration. (PR #743 & Closes Isssue #742)
• This adds error flags and exception messages to the spans for
  metadata, suggest, and bigtable writes when the chain of futures
  fails. The same exceptions are also logged. Previously some
  exceptions, such as grpc errors, could be masked by sl4j settings.
  The trace for a metric write was cleaned up to remove several
  intermediary spans. These spans did not have useful information and
  had no branching paths, so they were just clutter in the overall
  trace. (PR #740 & Closes Issue #724)

Release 2.3.11

• Moves Tdigest stat computation to SharedGroups combine phase. (Part 1 of 2) (#734)
• Add distribution query integration test. (Part 2 of 2) (#737)

2.3.10

• Add distribution data points aggregation core components. The implementation follows the same paradigm as existing aggregation instance such as sum and average. (#728)
• Update Checkstyle version from 6.x to 8.x. (#726)
• Correct metadata Series getter defect for scenarios where indexResourceIdentifiers is true. (#731)

2.3.9

• Introduce a config variable, indexResourceIdentifiers to index resource identifiers in elasticsearch metadata. If configured as true, Resource Identifiers will be written to and indexed in elasticsearch metadata. indexResourceIdentifiers defaults to false if not specified in heroic config. (#722)