Schema Cache Improvements (#5612)

* Cache Improvements

* improve tests

* more tests

* clean-up

* test with singlecache

* ensure indexes exists

* remove ALL_KEYS

* Add Insert Test

* enableSingleSchemaCache default true

* Revert "enableSingleSchemaCache default true"

This reverts commit 323e7130fb8f695e3ca44ebf9b3b1d38905353da.

* further optimization

* refactor enforceFieldExists

* coverage improvements

* improve tests

* remove flaky test

* cleanup

* Learned something new

src/Controllers/DatabaseController.js

@@ -844,7 +844,6 @@ class DatabaseController {
           : schemaController.validatePermission(className, aclGroup, 'create')
         )
           .then(() => schemaController.enforceClassExists(className))
-          .then(() => schemaController.reloadData())
           .then(() => schemaController.getOneSchema(className, true))
           .then(schema => {
             transformAuthData(className, object, schema);