[Elastic Agent] New input metrics dashboards and updated field mappings

[P1llus]

HTTPJSON, HTTP Endpoint, Filestream and CEL inputs has input metrics added, so new and updated dashboards was needed.

Added field mapping definitions for a few fields that made it hard to filter on logs in filebeat input logs.

Currently Azure Eventhub and GCP Pubsub still requires new dashboards.

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.

Related issues

• Relates https://github.com/elastic/security-team/issues/6362

Screenshots

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Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

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Build stats

• Start Time: 2023-12-11T12:12:03.814+0000

• Duration: 15 min 4 sec

Test stats 🧪

Test	Results
Failed	0
Passed	44
Skipped	0
Total	44

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🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	100.0% (0/0)	💚
Files	100.0% (0/0)	💚 4.396
Classes	100.0% (0/0)	💚 4.396
Methods	33.333% (28/84)	👎 -60.901
Lines	100.0% (0/0)	💚 9.615
Conditionals	100.0% (0/0)	💚

[leehinman]

LGTM

[elasticmachine]

Package elastic_agent - 1.18.0 containing this change is available at https://epr.elastic.co/search?package=elastic_agent