RPM `other.xml` updater

What does this MR do and why?

Extends BuildOtherXml builder services with build_new_node function to update existed xml files with metadata from new packages. Added more fake data to spec payload

Screenshots or screen recordings

How to set up and validate locally

1. Generate empty xml

empty = Packages::Rpm::RepositoryMetadata::BuildOtherXml.new.execute

2. Set variable with parsed RPM package metadata

data = Gitlab::Json.parse(File.open('spec/fixtures/packages/rpm/payload.json').read).with_indifferent_access

3. Call service again passing empty xml and data

Packages::Rpm::RepositoryMetadata::BuildOtherXml.new(xml: empty, data: data).execute

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #372735 (closed)