Exclude all CodeQL code-scanning queries of "Note" severity

[imnasnainaec]

To make the code-scanning more useful and less annoying, we can exclude all "note" severity queries. Drops us from ~2700 to 725 alerts: https://github.com/sillsdev/libpalaso/security/code-scanning?query=pr%3A1402+tool%3ACodeQL+is%3Aopen

Using documentation from:

• https://docs.github.com/en/code-security/code-scanning/creating-an-advanced-setup-for-code-scanning/customizing-your-advanced-setup-for-code-scanning#example-configuration
• https://codeql.github.com/docs/writing-codeql-queries/metadata-for-codeql-queries/
• https://colinsalmcorner.com/fine-tuning-codeql-scans/#widening-the-filter

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This change is 

[imnasnainaec]

@tombogle I see two rules (cs/missed-readonly-modifier and cs/xmldoc/missing-summary) cluttering your current pr and thought you might have input on what to exclude.

[github-actions]

Palaso Tests

     4 files  ±0       4 suites  ±0   15m 5s ⏱️ - 3m 10s
 4 902 tests ±0   4 674 ✅ ±0  228 💤 ±0  0 ❌ ±0 
15 957 runs  ±0  15 273 ✅ ±0  684 💤 ±0  0 ❌ ±0 

Results for commit 9cc0d02. ± Comparison against base commit 3813e6c.

♻️ This comment has been updated with latest results.

[imnasnainaec]

A simple alternative to specific "note" exclusions would be to switch from security-and-quality to security-extended.

EDIT: This dropped too many rules, so working on filtering by severity instead.