Add support for Jenkins BOM as a source of plugin versions when using YAML or TXT plugin lists

Jenkins Plugin Bill of Materials provides a list of plugins which are cross-verified to some extent: https://github.com/jenkinsci/bom . When using pom.xml as a plugin list input, it is possible to use BOM via Maven features. But it is not possible for a YAML configuration. It would be awesome to support it so that users can delegate version management of some components they bundle

Example of a cocnfig file:

```yaml
versionSources:
- bom:
baseline: 2.277
version: 27
plugins:
- artifactId: git
- artifactId: job-import-plugin
source:
version: 2.1
- artifactId: docker
- artifactId: cloudbees-bitbucket-branch-source
- artifactId: script-security
- artifactId: workflow-step-api

```