Previously, WarLauncher included its root on the classpath. It also used
a filtered version of its root archive to hide both the WEB-INF and
META-INF directories. This meant that files in WEB-INF and META-INF
could be found by the classloader (as they were on the classpath) but
could not be read as the filtered archive was hiding them.

This commit updates WarLauncher to remove the root of the war file from
the classpath. It also removes the filtering of the archive, thereby
allowing files in META-INF and WEB-INF to be accessed via the
ServletContext.

Closes gh-1792

Previously, the tests for Boot’s various logging systems used the
JVM’s default temp directory as the location of the spring.log file.
It is suspected that this was causing intermittent CI failures when
multiple Boot builds were running in parallel and tests were checking
for the presence of the spring.log file in the shared temp directory.

This commit updates AbstractLoggingSystemTests to configure a local
temp directory for the duration of the tests, thereby hopefully
eliminating failures caused by concurrent builds sharing the same
directory.

The previous attempt at fixing the intermittent CI failures (504de8a7)
has been removed as part of this commit as it did not fix the problem.

Closes gh-1864

Conflicts:
	spring-boot-dependencies/pom.xml

Closes gh-1785

Closes gh-1890

Closes gh-1895

Closes gh-1894

Closes gh-1892

Closes gh-1891

Closes gh-1889

Closes gh-1888

Closes gh-1887

Closes gh-1886

Closes gh-1885

Closes gh-1805

Provide a default UTF-8 encoding for HTTP requests and responses unless
specified otherwise.

Fixes gh-1182

Closes gh-1893

Conflicts:
	spring-boot-dependencies/pom.xml

The exception message for a connection timeout has been updated to
include the timeout period. The tests for the sample have been updated
accordingly.

Closes gh-1884

Closes gh-1883

Closes gh-1882

Closes gh-1881

Closes gh-1880

Closes gh-1879

Closes gh-1878

Closes gh-1877

Closes gh-1876

Closes gh-1875

Update TypeElementMembers to correctly detect builder style setters.
The previous logic could fail because of the crazy way that TypeMirror
implements its equals() method.

Fixes gh-1859
See gh-1854

Update ConfigurationMetadataAnnotationProcessor to only write non-empty
meta-data files.

Fixes gh-1858

Remove the JpaBaseConfiguration.configure() method since it is no
longer called.

Fixes gh-1865

Update the InitializrService so that a 'SpringBootCli' User-Agent header
is sent with each request. This should allow the server-side code to
gracefully evolve the JSON format if needed.

Fixes gh-1869

Fixes gh-1712

Update MultipartAutoConfiguration to detect any MultipartResolver beans
rather than just StandardServletMultipartResolvers.

Fixes gh-1857