[Bitbucket] Add Bitbucket package

[legoguy1000]

What does this PR do?

Adds a Bitbucket package to ingest the audit logs

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 packages/atlassian_bitbucket
elastic-package build && elastic-package stack down && elastic-package stack up --version 8.0.0-SNAPSHOT -d -v && eval "$(elastic-package stack shellinit)" && elastic-package test -v

Related issues

Screenshots

[elasticmachine]

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Build stats

• Start Time: 2021-12-13T06:35:43.337+0000

• Duration: 16 min 39 sec

• Commit: 039b20b

Test stats 🧪

Test	Results
Failed	0
Passed	7
Skipped	0
Total	7

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