Fixing antlr dependencies

[nielsbasjes]

Changes in this pull request:

• Problem to fix: The spring-ai-template-st module references the Token class from Antlr to access something in the template library. The template library uses Antlr 3 and the added dependency is the Antlr 4 runtime. It is a miracle that actually worked.

• Solution: Shade the already provided antlr-runtime (which is V3) and relocate it to a package that is chosen to avoid conflicts with any downstream consuming application.

• Problem to fix: antlr4-runtime conflicts when used with other libraries that use Antlr4. #5748
  When using Antlr in a project the antlr runtime needs to be an exact matched version of the plugin used to generate the code. If you have a downstream project that has a different dependency that also uses Antlr then there is a high probability there is a conflict in the used runtime and a least one of the components will not work.

• Solution: Shade the applicable antlr4-runtime and relocate it to a package that is chosen to avoid conflicts with any downstream consuming application. Also: The generated Anltr4 code was committed to the repo which is not needed at all.

• Chore: Updating to the latest Antlr4 version.

NOTE: I used this pattern to relocate the antlr runtime to. This can be changed to anything as long as the new package avoids conflicts with any downstream users.
shaded.${project.groupId}.${project.artifactId}.library.org.antlr

[nielsbasjes]

Note: The ST4 must be shaded in also because that is the main library that needs the shaded antlr-runtime also.