Remove redundant metainfo_repos.global_bind, output_manifest specification

• the GitANNSvc, if a requested key XYZ cannot be found in the 'master' branch, will automatically also look in the branch key-XYZ - hence there is no need to specify extra-central-tags which follow that format.
• in case the output_type is 'ROOT', there is no need to specify a separate output_manifest_file, as the information will be written to the FSR of the output (ROOT) file. Absence of this information from the FSR of the output file should be considered a configuration mistake, and should be fixed by ensuring the information does end up in the FSR, and not by (also) putting things into a manifest file. The unnecessary use of manifest files can thus only serve to hide mistakes that ought to be spotted and fixed, and thus continued use of the manifest file should thus be considered as harmful, and a bug.

note: this MR is a pre-requisite to LHCb!5393, which will be more strict on enforcing encoding keys to be written into the FSR, and avoiding writing them to either git or manifest files if (and only if) the output file support FSRs