Closes gh-1774

Closes gh-1767

Spring IO Platform already provides dependency management for JavaMail.
This commit updates Boot’s new JavaMail dependency management to align
with the Platform, thereby allowing the Platform to inherit Boot’s
dependency management instead of defining its own.

This commit adds a new starter to auto-configure a MailSender when the
necessary classes are present and when the property "spring.mail.host" is
set.

The auto-configuration also accepts any arbitrary properties that
JavaMail might need using the "spring.mail.properties" prefix.

Fixes gh-1760

There actually isn't anything much we can (or should) change here. Spring always
copies PropertySources and profiles down into the child context when you set its parent.
That seems sensible. So you can add a new profile in a child context but it will always
"inherit" from its parent.

See gh-1776

* whitelabel-typo:
  Fix a typo in error.whitelabel.enabled

Conflicts:
	spring-boot-dependencies/pom.xml

Closes gh-1782

Fixes #1781

also rename spring-cloud starter

The CI build is failing, but, for some reason, the same tests are
working fine on developer machines. This commit increases the level
at which the logging calls are being made to severe in the hope that
some CI-specific configuration is filtering out the calls when
they're at info level.

Fixes gh-1753

Fixes gh-1612, Fixes gh-1770

1 disable the file output unless LOG_FILE is set
2 make the console optional

fixes: gh-1612

Fixes gh-1773

Then we can optionally find a non-anonymous principal if there
is one. If the user is anonymous then the health result is cached
up to endpoints.health.ttl (default 1000ms) to prevent a DOS attack.

Fixes gh-1353

Closes gh-1765

See gh-1762

This reverts commit d6621e62. I think
the test failure might be a bug in Liquibase:
https://liquibase.jira.com/browse/CORE-2094

Fixes gh-1382

Fixes gh-1752

Fixes gh-1762, gh-1731