minor x-bte refactoring: drop use of useTemplating field

[colleenXu]

[EDITS will be made to this post as I set up the x-bte refactoring issues.]

This is a less-important + probably-easy part of "x-bte refactoring". Previously brought up here under "remove unneeded fields".

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We created the useTemplating field during a past enhancement/refactoring of x-bte annotation.

Features of that past enhancement (that I remember)

• changing the sub-query construction keyword for input IDs to queryInputs
• using nunjucks as a "templating language" to construct more complicated sub-queries
  • issues:
    • Design a Query Builder which supports querying multiple fields in BioThings API in batch mode #147
    • support templating language when constructing API calls call-apis.js#26
  • PRs with info on what was implemented
    • Support Nunjucks templating engine for API call construction call-apis.js#30
    • Templating revision call-apis.js#31
• doing scrolling-POST queries for BioThings APIs:
  • issues:
    • scrolling POST-queries to retrieve all hits (pending biothings apis only for now) #483
    • Update SmartAPI annotations: useTemplating and consistent ordering #511
  • PR with info Use biothings with_total to efficiently batch query call-apis.js#59

While it was useful when first implementing the features + migrating all x-bte annotations over to the new features, now all x-bte annotation has useTemplating: true and uses the features...

So I think we could:

• make useTemplating: true behavior the default, so it can be removed from x-bte annotation
• remove useTemplating: false support
• update all x-bte annotation to remove the useTemplating: true lines

[colleenXu]

Currently part of #748 (comment)