MM-63652: Transition gossip encryption functionality to GA (#33349) (#33429)

Create a new config setting, and migrate the old values to new.

https://mattermost.atlassian.net/browse/MM-63652

Skip-Enterprise-PR: true

```release-note
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* fix i18n

also fix unit tests

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* For fresh installations, default to true

```release-note
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```

* gofmt files

```release-note
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* Fixing some more strings

```release-note
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* Update e2e tests

```release-note
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e2e-tests/cypress/tests/support/api/on_prem_default_config.json

@@ -471,7 +471,7 @@
         "AdvertiseAddress": "",
         "UseIPAddress": true,
         "EnableGossipCompression": true,
-        "EnableExperimentalGossipEncryption": false,
+        "EnableGossipEncryption": false,
         "ReadOnlyConfig": true,
         "GossipPort": 8074
     },