Update SSL cipher configuration and give options to switch

[mrrobot47]

The default SSL cipher configuration till now on EasyEngine is based on the Mozilla intermediate profile which provided compatibility with clients back to Firefox 1, Chrome 1, IE 7, Opera 5, Safari 1, Windows XP IE8, Android 2.3, Java 7. This configuration also enabled HSTS, PFS, OCSP stapling and SSL session caches. Currently, TLS 1.0, 1.1 and 1.2 are supported in it.

As, TLS 1.0 is deprecated and it reached its end of life on June 30, 2018.

It is time to switch to the default SSL cipher configuration to the: Mozilla modern profile. This profile is compatible with clients back to Firefox 27, Chrome 30, IE 11 on Windows 7, Edge, Opera 17, Safari 9, Android 5.0, and Java 8.

Apart from switching to Mozilla modern profile as default, need to add config option to switch to all the supported policies here.

Thus after implementation, ee config set ssl-policy <valid-policy> can be used to set desired policy.

Where <valid-policy> from here include:
Mozilla-Old, Mozilla-Intermediate, Mozilla-Modern, AWS-TLS-1-2-2017-01, AWS-TLS-1-1-2017-01, AWS-2016-08, AWS-2015-05, AWS-2015-03 and AWS-2015-02.