Remove now-unused stage to hide imported IdPs.
Increased metadata validity interval to 21 days for the Christmas and New Year holiday period.
Pivot to make hide from discovery entity category primary.

We still use the legacy marker in fragment files, but all decisions are made on the basis of the entity category.
Remove a couple of redundant stages.

We have removed all KeyName elements from UK federation metadata, so we no longer need to explicitly strip them on export.
Remove HideFromWAYF element and wayf namespace from test aggregate.
Hoist mdattr and saml namespace prefixes in the test aggregate.