Editor configuration / Add capability to display view according to session and metadata

Views can be displayed based on the metadata record content or the service information.

Example: Only display view if standard name contains a value:
```
 <view 
  name="medsea" 
  displayIfRecord="contains(gmd:MD_Metadata/gmd:metadataStandardName/gco:CharacterString, 'MedSea')"
```

Example: Only display view if current user is an administrator.
```
<view
  name="medsea" 
  displayIfServiceInfo="count(session[profile = 'Administrator']) = 1"
```
ServiceInfo allows to access any Jeeves /root/gui elements.

This is useful when you only need to create a custom editor view for some records and avoid to create a complete schema plugin for that.