[Snort] Add Snort Integration

[legoguy1000]

What does this PR do?

Add Snort integration

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.
• If I'm introducing a new feature, I have modified the Kibana version constraint in my package's manifest.yml file to point to the latest Elastic stack release (e.g. ^7.13.0).

Author's Checklist

• [ ]

How to test this PR locally

cd integrations/packages/snort
elastic-package stack down && elastic-package build && elastic-package stack up -d -v -p default && eval "$(elastic-package stack shellinit)" && elastic-package test  -v

Related issues

• Closes Migrate Snort module #937

Screenshots

[elasticmachine]

💚 Build Succeeded

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Build stats

• Start Time: 2021-09-30T09:48:19.233+0000

• Duration: 14 min 51 sec

• Commit: 3adccf3

Test stats 🧪

Test	Results
Failed	0
Passed	11
Skipped	0
Total	11

🤖 GitHub comments

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

• /test : Re-trigger the build.

[P1llus]

/test

[P1llus]

/test

[P1llus]

If you could bump minimum version to 7.16 I could merge right away

[elasticmachine]

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