[AWS][ECS] Add ECS metric types for TSDB support

[constanca-m]

What does this PR do?

Add field metric type to the ECS data stream for TSDB support.

Details

All metrics are gauge as they both increment and decrement.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.

How to test this PR locally

Refer to #5894

Related issues

• Relates to [AWS][ECS] TSDB Enablement #5894

[elasticmachine]

💚 Build Succeeded

the below badges are clickable and redirect to their specific view in the CI or DOCS

Expand to view the summary

Build stats

• Start Time: 2023-05-04T08:25:01.228+0000

• Duration: 52 min 55 sec

Test stats 🧪

Test	Results
Failed	0
Passed	188
Skipped	4
Total	192

🤖 GitHub comments

Expand to view the GitHub comments

To re-run your PR in the CI, just comment with:

• /test : Re-trigger the build.

[elasticmachine]

🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (15/15)	💚
Files	93.75% (15/16)	👍
Classes	93.75% (15/16)	👍
Methods	86.131% (236/274)	👍
Lines	85.925% (7387/8597)	👍
Conditionals	100.0% (0/0)	💚

[elasticmachine]

Package aws - 1.34.3 containing this change is available at https://epr.elastic.co/search?package=aws