[SSL Version policies] Update description, docs and add default values

[htcfreek]

Fixes #1039.

This PR does the following:

• It updates the documentation and adds the default value for both policies to it.
• It fixes the explanation of SSLVersionMin policy by changing the default value to TLS1.2 in the ADMX templates for Windows.
• It adds defaultValue property to the presentation definition in the ADMX templates for Windows. (Now when the policy is set to enabled the default value of FF is selected automatically.)

[mkaply]

Sorry I haven't reviewed this yet. I'll get to it this week.

My biggest question is don't we need to keep the old policy around so that people can unset it to use the new policy? Usually I deprecate something because otherwise someone can't ever change the old values once we remove them.

[htcfreek]

These are only visual changes. It only updates the description text and the preselected value.

There are no changes on the registry part. And I didn't remove any of the available SSL versions.

[mkaply]

Thank you for this!