[MBUILDCACHE-94] Provide a build cache report on builds

**[Marquis Wang](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=mwang5)** opened **[MBUILDCACHE-94](https://issues.apache.org/jira/browse/MBUILDCACHE-94?redirect=false)** and commented

When building with the build cache, it would be really helpful to provide a report of which modules were unable to utilize and cache, as well as information about why.

Right now, when looking at build cache performance, we can use `maven.build.cache.failFast` and `maven.build.cache.baselineUrl` to understand which module(s) were unable to utilize the build cache and why. However, this process is entirely manual.

It would be really helpful to provide some base cache statistics on every run, even if no baselineUrl is provided. That way, we can gather overall statistics and figure out how to change our project to better utilize the cache.

For example, we have a multi-module project with hundreds of modules. I want to know if there is one module that is constantly changing and is depended on (possibly unnecessarily) by lots of other modules, which is causing cache misses.

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No further details from [MBUILDCACHE-94](https://issues.apache.org/jira/browse/MBUILDCACHE-94?redirect=false)

Start by reviewing the build-cache extension's existing handling of maven.build.cache.failFast and maven.build.cache.baselineUrl. Determine where per-run cache results are available and what statistics would explain modules that could not use or populate the cache. Done means every run provides useful cache statistics without requiring a baselineUrl.

Written by the indexing model from the issue text.