Adds support for storing mustache based query templates that can later be filled
with query parameter values at execution time. Templates may be both quoted,
non-quoted and referencing templates stored in config/scripts/*.mustache by file
name.
See docs/reference/query-dsl/queries/template-query.asciidoc for templating
examples.
Implementation detail: mustache itself is being shaded as it depends directly on
guava - so having it marked optional but included in the final distribution
raises chances of version conflicts downstream.
Fixes#4879
If a type or path is missing in the REST test yaml file, it is
automatically replaced with _all. This makes it hard to test changes
in the api, for example adding the possibility to leave the index
blank in addition to _all and * in the uri.
closes#4657
Isabel Drost-Fromm
Britta Weber
Honza Král
Boaz Leskes
Spencer Alger
Karel Minarik