NEW: Bulk loader

[unclecheese]

Resolves: #367
Docs: silverstripe/silverstripe-framework#10203

elemental: # arbitrary key to define what this set of loaders is doing
  load:
    inheritanceLoader:
      include:
        - DNADesign\Elemental\Models\BaseElement
  apply:
    fields:
      '*': true
    operations:
      read: true
      readOne: true
app:
  load:
    namespaceLoader:
      include:
        - 'App\Models\*'
      exclude:
        - 'App\Models\Secret\*'
  apply:
    fields:
      '*': true
    operations:
      '*': true

[emteknetnz]

Looks good, some very minor things