Closes gh-13898

Closes gh-13912

Closes gh-7483

See gh-13917

Add an `DispatcherServletPath` interface which provides a much more
consistent way to discover the path of the main dispatcher servet.

Prior to this commit, auto-configurations would often make use of the
`ServerProperties` class to discover the dispatcher servlet path. This
mechanism isn't very explicit and also makes it hard for us to relocate
that property in Spring Boot 2.1.

This commit also reverts most of fddc9e9c since it is now clear that
the supporting multiple dispatcher servlet paths will be much more
involved that we originally anticipated.

Closes gh-13834

Update the root build POM so that the default profile is always active.
Prior to this commit the profile was to `activeByDefault` which meant
it was only active if no other profiles were enabled. When running in
Eclipse, the `m2e` profile is active, meaning the default profile was
disabled and `spring-javaformat` setting were not applied.

Closes gh-13900

Move the `eclipse.properties` file from `.eclipse` into `eclipse`
since the IDE plugin supports both.

Closes gh-13912

See gh-13898

See gh-13890

See gh-13742

This commit makes sure to unwrap any transaction aware cache before
collecting metrics for them.

Closes gh-13861

Fixes gh-13636

This commit rework 1189ccc9 to prevent a mutate call on the original
headers map.

Closes gh-13871

Co-authored-by: Andy Bell <andyrbell@gmail.com>

Closes gh-13863

* pr/13871:
  Polish "Use Collection.removeIf() where possible"
  Use Collection.removeIf() where possible

Closes gh-13871

See gh-13871

* pr/13813:
  Polish "Add metric description and base unit to metrics endpoint"
  Add metric description and base unit to metrics endpoint

Closes gh-13813

See gh-13813

* pr/13819:
  Polish "Upgrade to Micrometer 1.0.6"
  Upgrade to Micrometer 1.0.6

Closes gh-13819

See gh-13819