* Interpolate the field property in elastic search term queries

* more defensive interpolation of query.field in ES templates

Fixes #8750.

This should close the bug #8773

When converting Prometheus results to table, handle the case where the returned series have non-uniform sets of labels. (#8826)

Adds pragma and expires headers for API calls so that IE11 does not
cache GET calls. Ref #5356

"Metric Lookup" row in Query editor was broken :(

If a dashboard has a null value for updated_by then the migration
for the dashboard version table fails. This change uses coalesce to
set -1 instead of null when inserting into the created_by column
which has a non-null constraint. Fixes #8783.

If a dashboard has a null value for updated_by then the migration
for the dashboard version table fails. This change uses coalesce to
set -1 instead of null when inserting into the created_by column
which has a non-null constraint. Fixes #8783.

This reverts commit 8634c9d4.

Fixes #5356. Internet Explorer aggressively caches GET requests which
means that all API calls fetching data are cached. This fix adds a
Cache-Control header with the value no-cache to all GET requests to
the API.