To esv2yaml add domain specific HST configuration support for the channels move

We created esv2yaml (see Esv2Yaml.java in HCM's migration module) to migrate the old XML bootstrap resources to YAML. During the migration, if the module being processed contains to-be-adjusted HST configuration (i.e. mounts with channelpath properties or hst:channel nodes), the corresponding definitions should need to be migrated to their intended location (or deleted).

The upgrade documentation should clearly describe what the tool attempts to achieve, such that users of the tool can (should!), upon applying it successfully, validate the correctness of the result before continuing to apply the YAML definitions to a repository.