[#51185083] Refactor location picker.

- Pull 'bindToSelectorViews' method to the base location picker.
- Remove state references in the picker views by adding corresponding methods to
the Selector and Schema views.
[#51185083] Refactorings.

- Use _.result instead of _.isFunction logic.
- Extract common behavior from schemasLoaded and databasesLoaded into collectionLoaded.
- Extract 'isHdfs' method in work flow execution location picker.