See gh-17875

* pr/17861:
  Map non-null LDAP properties

Closes gh-17861

The userDn and password in LdapContextSource are not nullable. The
default values for userDn and password in LdapProperties are null. When
the values are set to null there will eventually be a
NullPointerException during
AbstractContextSource#setupAuthenticatedEnvironment since HashTable
doesn't allow null for values.

See gh-17861

* pr/17805:
  Polish "Set up SpringLiquibase beans' dependencies by type rather than name"
  Add missing javadoc
  Set up SpringLiquibase beans' dependencies by type rather than name

Closes gh-17805

See gh-17805

See gh-17805

See gh-17805

* gh-17876:
  Test the Gradle Plugin against Gradle 5.6

Closes gh-17876

See gh-17876

* pr/17780:
  Polish "Expand documentation on remote devtools"
  Expand documentation on remote devtools

Closes gh-17780

See gh-17780

See gh-17780

Fixes gh-17843

Closes gh-12874

Closes gh-17842

Closes gh-17698

Closes gh-12874

Closes gh-17835

* pr/17835:
  Fix syntax errors in docs

Closes gh-17835

See gh-17835

Closes gh-16704

Closes gh-16853

* pr/17778:
  Polish "Configure a temporary directory with Undertow"
  Configure a temporary directory with Undertow

Closes gh-17778

See gh-17778

See gh-17778

* pr/17807:
  Polish "Fix annotation lookup on proxied EndpointExtension"
  Fix annotation lookup on proxied EndpointExtension

Closes gh-17807

See gh-17807

See gh-17807

Closes gh-17794

* pr/17774:
  Fix typo in assertion

Closes gh-17774

See gh-17774

Closes gh-17675

Closes gh-17786

Closes gh-17581