Add mysql_character_set

[gparent]

Add mysql_character_set which sets character-set-server in the [mysqld] section as per: https://dev.mysql.com/doc/refman/5.7/en/charset-applications.html

[stale]

This pull request has been marked 'stale' due to lack of recent activity. If there is no further activity, the PR will be closed in another 30 days. Thank you for your contribution!

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[gparent]

Unstale. Will close if not required once it gets a response.

[stale]

This issue is no longer marked for closure.

[bmillemathias]

I concur this would be good to have that.

[stale]

This pull request has been marked 'stale' due to lack of recent activity. If there is no further activity, the PR will be closed in another 30 days. Thank you for your contribution!

Please read this blog post to see the reasons why I mark pull requests as stale.

[stale]

This pull request has been closed due to inactivity. If you feel this is in error, please reopen the pull request or file a new PR with the relevant details.