Previously to this commit, transaction management was only enabled when
a `DataSource` is configured. The processing of `@Transactional`
annotations are now enabled as long as a `PlatformTransactionManager` is
present.

Also, the `spring.aop.proxy-target-class` is now honoured if set, still
defaulting to CGLIB mode.

Closes gh-8434

* pr/8781:
  Polish "Use git.commit.id.abbrev if present" contribution
  Use git.commit.id.abbrev if present

Closes gh-8781

Currently GitProperties always shortens the property git.commit.id to an
hardcoded length of 7.

However, both the Maven plugin git-commit-id-plugin and the Gradle
plugin gradle-git-properties are now providing the property
git.commit.id.abbrev along with the propery git.commit.id.
Moreover, the Maven plugin allows to customize the length of the
abbreviated commit ID with the configuration abbrevLength. The Gradle
plugin doesn't allow (yet) to configure this length.

Closes gh-8773

Closes gh-8767

* pr/8660:
  Fix test assertions

Closes gh-8660

* pr/8678:
  Fix propdeps-plugin url in doc

Closes gh-8678

See gh-8698

* pr/8718:
  Fix typo

Closes gh-8718

Closes gh-8498

Closes gh-8746

Closes gh-8745

Closes gh-8744

Closes gh-8743

Closes gh-8742

Closes gh-8741

Closes gh-8740

Closes gh-8739

Closes gh-8738

Closes gh-8734

Closes gh-8733

Closes gh-8732

Closes gh-8731

Closes gh-8730

Closes gh-8729

Closes gh-8728

Closes gh-8727

Closes gh-8726

Closes gh-8725

Closes gh-8724

Closes gh-8723

Closes gh-8722

Closes gh-8721