Update configuration properties support to allow the `@Component`
annotation to be used on `@ConfigurationProperties` beans as long
as they are mutable.

This restores the behavior of Spring Boot 2.1 for mutable beans whilst
still allowing us to enforce the stricter rules for immutable value
object configuration properties.

Closes gh-18138

* pr/18187:
  Fix typo in javadoc

Closes gh-18187

See gh-18187

* pr/18170:
  Polish "Remove management.health.status.order from docs"
  Fix link formatting in custom HealthIndicator section
  Remove management.health.status.order from docs

Closes gh-18170

See gh-18170

See gh-18170

See gh-18170

This commit moves `@ConfigurationProperties` to the `@Bean` factory
method as this is unusual to put it at class level if it's exposed
that way.

As HealthIndicatorProperties has a constructor, this makes sure that
the annotation processor enables JavaBean binding mode.

This commit makes sure that a ConfigurationProperties type contributed
by a `@Bean` factory method uses properties binding regardless of the
presence of a matching constructor.

`@Bean` method makes sure the user is in control and will be responsible
of creating the instance. As a result, binding of properties will not
happen there and therefore can only happen with regular JavaBean
accessors.

Closes gh-18184

Closes gh-18186

Closes gh-14022

Closes gh-18185

* pr/18175:
  Simplify code

Closes gh-18175

See gh-18175

Closes gh-18182

Closes gh-18181

Closes gh-18180

* pr/18172:
  Fix broken links for master snapshot builds

Closes gh-18172

See gh-18172

Closes gh-17903

Closes gh-17899

Closes gh-17902

Closes gh-17898

Closes gh-17901

Closes gh-17897

Previously, a number of usages of @ConditionalOnMissingBean prevented
a bean that implements an auto-configured bean's "main" interface from
causing the auto-configuration of the bean to back off. This would
happen when @ConditionalOnMissingBean did not specify a type, the
@Bean method returned the bean's concrete type, and that concreate
type implements a "main" interface.

This commit updates such usages of @ConditionalOnMissingBean to
specify the "main" interface as the type of the bean that must be
missing. This will allow, for example, the auto-configured
MongoTemplate bean to back off when a MongoOperations bean is defined.

Closes gh-18168

Previously, calling getComment() on a nested jar file would result
in the outer jar file's comment being returned.

This commit updates the loader's JarFile to read the file's comment
from the central directory end record and return it from getComment().

Fixes gh-18128

Closes gh-18167

* gh-18164:
  Test the Gradle Plugin against Gradle 5.6.2

Closes gh-18164

See gh-18164

Closes gh-18165

Fixes gh-18153

See gh-18162

Fixes gh-18163