Instead of using keyParamName of CodegenSecurity, a hard coded token name of "api_key_query" was used to parse API tokens in query strings.

This PR changes this string to the template value {{{keyParamName}}}.

Closes #7904

Technical committee: @frol (2017/07) @farcaller (2017/08) @richardwhiuk (2019/07) @paladinzh (2020/05)

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