chore: update readme following sec recommendations MCP-198

[himanshusinghs]

Proposed changes

This commit ensures that our examples promote use of environment variables for providing sensitive configuration options. Additionally we callout, where ever necessary, our recommendation of choosing env variables over command line arguments for the same.

Checklist

• I have signed the MongoDB CLA

[Copilot]

Pull Request Overview

This PR updates the README to improve security by promoting the use of environment variables for sensitive configuration instead of command line arguments. The changes align with security recommendations to prevent sensitive data exposure through process lists and system logs.

• Added security recommendations highlighting the use of environment variables over command line arguments
• Updated all configuration examples to use environment variables for sensitive data (connection strings, API credentials)
• Restructured sections to emphasize secure configuration practices

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[nirinchev]

Seems reasonable, though note that export foo=bar works in bash, but not in pwsh or cmd. Would be great if we could show both ways of configuring things - e.g. in <details> or something similar.

[nirinchev]

Docker noob here, but does this work by passing through the environment vars?

[himanshusinghs]

yup yup. We just need to make sure the env var is set and docker will pull the value from the referred env var name.

[blva]

LGTM

[himanshusinghs]

@blva @nirinchev I have added cmd and powershell examples as well and cross referenced them, if any of you want to take another look.

[coveralls]

Pull Request Test Coverage Report for Build 17649080824

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 6 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.1%) to 81.204%

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Files with Coverage Reduction	New Missed Lines	%
src/common/connectionManager.ts	6	87.78%

Totals
Change from base Build 17647912778:	-0.1%
Covered Lines:	4774
Relevant Lines:	5784

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💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 17649033546

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 6 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.1%) to 81.204%

---

Files with Coverage Reduction	New Missed Lines	%
src/common/connectionManager.ts	6	87.78%

Totals
Change from base Build 17647912778:	-0.1%
Covered Lines:	4774
Relevant Lines:	5784

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💛 - Coveralls