Partially remove mentions of lgtm.com from the CodeQL documentation

[jf205]

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LGTM.com is being deprecated (see https://github.com/orgs/community/discussions/29534) so we are updating the docs.

This PR addresses the simplest updates including:

• CodeQL CLI docs
• CodeQL for VS Code docs
• Everything in CodeQL queries apart from Defining the results of a query

CodeQL language guides and QL tutorials are trickier so will be addressed separately.

CodeQL overview and QL language reference don't require any changes.