More flexible OTLP per meter configuration

[lenin-jaganathan]

#5974 introduced the support for configuring HistogramFlavour/buckets per meter for OTLPMeterRegistry. This was done as part of a configuration that was supplied during the registry creation and does not allow overriding via APIs. This configuration does a full match of the meter name and requires the fully qualified meter name to be provided and this can get longer when we need to supply configuration to a family of meters.

Spring boot has a solution to address this issue by supporting the prefix and if there are more values the longest match wins. If users can supply a Function to be applied for determining these values also be an option to try out.

[shakuzen]

In the end, we changed the lookup logic to match the mentioned logic used for some Spring Boot configuration properties related to configuring MeterFilters. That is, a longest match by dot-separated segment will be used to apply the per-meter config even in cases where it is not an exact match. See the updated JavaDoc for the methods on OtlpConfig for an example. We did not make this logic customizable, as it didn't seem necessary for the underlying issue (configuring groups of meters). If someone else has the need for that, please let us know the details and we can re-consider that change in a separate issue.