feat: Add jsonnet-bundler support (#12720)

docs/usage/configuration-options.md

lib/manager/api.ts

...-bundler/__fixtures__/jsonnetfile-local-dependencies.json

...net-bundler/__fixtures__/jsonnetfile-no-dependencies.json

...r/jsonnet-bundler/__fixtures__/jsonnetfile-with-name.json

lib/manager/jsonnet-bundler/__fixtures__/jsonnetfile.json

...ager/jsonnet-bundler/__snapshots__/artifacts.spec.ts.snap

...anager/jsonnet-bundler/__snapshots__/extract.spec.ts.snap

lib/manager/jsonnet-bundler/artifacts.spec.ts

lib/manager/jsonnet-bundler/artifacts.ts

lib/manager/jsonnet-bundler/extract.spec.ts

lib/manager/jsonnet-bundler/extract.ts

lib/manager/jsonnet-bundler/index.ts

lib/manager/jsonnet-bundler/readme.md

lib/manager/jsonnet-bundler/types.ts

lib/util/exec/buildpack.ts