Elasticsearch: Fix handling of inline scripts in different ES versions

[Elfo404]

What this PR does / why we need it:
Aggregations' Inline scripts prior to ES 5.6 had to be defined like (VERSION B)

"script": {
  "inline": "script_value"
}

in 5.6, the former was deprecated in favor of:

"script": {
  "source": "script_value"
}

or, as a shorthand: (VERSION A)

"script": "script_value"

In Grafana < 7.4 we were storing the query model like VERSION B, in >=7.4 like VERSION A.

This PR fixes 2 things:

• Handling different Elasticsearch versions requirements for the script field (What the linked issue is about)
• Applying the same logic on the backend for alerting queries (it wasn't implemented before)

Which issue(s) this PR fixes:

Fixes #34028
Closes #34030

Special notes for your reviewer:

I created a docker block in devenv for ES 5.0 and moved elastic5 to elastic56 as it was using elasticsearch 5.6. I'm not able to start both at the same time as somehow when starting both one of the nodes elects itself as master and shuts down the other. I tried working around this by setting different configurations but none of them did the job.

I also created a row in http://localhost:3000/d/fuFWehBmk/datasource-tests-elasticsearch-comparison (Datasource tests -> Elasticsearch comparison) that has queries using both the new and old script format.

as mentioned above, running 2 ES version at the same time doesn't work ATM, the best way I can think of to test this is therefore running make devenv sources=elastic5, check that both series are being shown, then make devenv sources=elastic56 and repeat.

Alerting as well works as expected with both formats and both ES version, testing is a bit more trickier as the datasource is templated, so make sure to pick the one you are testing against before testing the alerting rule:
->

Alerting tests:

ES 5.0

New Script format (VERSION A, Query A)

OLD Script format (VERSION A, Query B)

ES 5.6

New Script format (VERSION A, Query A)

Old Script format (VERSION B, Query B)

PS: Don't forget to run ./setup.sh in devenv to get updates to data sources and dashboard :)

[Chris7]

Just wanted to say you're awesome. Thanks for the quick turnaround!

[aocenas]

Looks good 👍