Replace downloadJar with downloadJarFromURL

[jan-vcapgemini]

All usages of downloadJar can be replaced with downloadJarFromURL. The old method downloadJar is way too adjusted to old monolithic templates and can be removed. The old update command (download of monolithic template jars) will be removed anyway.

https://github.com/devonfw/cobigen/blob/5c64a1e83cf117d768c30940245b38accf1edf3d/cobigen-cli/cli-systemtest/src/test/java/com/devonfw/cobigen/cli/systemtest/AdaptTemplatesCommandIT.java#L111-L112

https://github.com/devonfw/cobigen/blob/5c64a1e83cf117d768c30940245b38accf1edf3d/cobigen/cobigen-core-api/src/main/java/com/devonfw/cobigen/api/util/TemplatesJarUtil.java#L48-L90

https://github.com/devonfw/cobigen/blob/5c64a1e83cf117d768c30940245b38accf1edf3d/cobigen/cobigen-core-api/src/main/java/com/devonfw/cobigen/api/util/TemplatesJarUtil.java#L92-L99

Can be removed: https://github.com/devonfw/cobigen/blob/5c64a1e83cf117d768c30940245b38accf1edf3d/cobigen/cobigen-core-api/src/main/java/com/devonfw/cobigen/api/util/TemplatesJarUtil.java#L140

Can be removed: https://github.com/devonfw/cobigen/blob/5c64a1e83cf117d768c30940245b38accf1edf3d/cobigen/cobigen-core-api/src/main/java/com/devonfw/cobigen/api/util/TemplatesJarUtil.java#L153