MM-41988 Updated links to legacy domain about.mm.com (#19552)

* Updated links to legacy domain about.mm.com

* Legacy link updates

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* Reverting - only need to change en.json

* about.mm.com URL updates

* mattermost.org URL updates

* forum.mm.org URL update

* Update .github/ISSUE_TEMPLATE.md

* Update .github/ISSUE_TEMPLATE.md

* Un-deleted language files

* Update README.md

* Update tests/test-config.json

* fix some test due to url updating (#19787)

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>
Co-authored-by: Harrison Healey <harrisonmhealey@gmail.com>
Co-authored-by: Ibrahim Serdar Acikgoz <serdaracikgoz86@gmail.com>

tests/test-config.json

@@ -180,11 +180,11 @@
         "ShowFullName": true
     },
     "SupportSettings": {
-        "TermsOfServiceLink": "https://about.mattermost.com/default-terms/",
-        "PrivacyPolicyLink": "https://about.mattermost.com/default-privacy-policy/",
-        "AboutLink": "https://about.mattermost.com/default-about/",
-        "HelpLink": "https://about.mattermost.com/default-help/",
-        "ReportAProblemLink": "https://about.mattermost.com/default-report-a-problem/",
+        "TermsOfServiceLink": "https://mattermost.com/terms-of-use/",
+        "PrivacyPolicyLink": "https://mattermost.com/privacy-policy/",
+        "AboutLink": "https://mattermost.com/default-about/",
+        "HelpLink": "https://mattermost.com/default-help/",
+        "ReportAProblemLink": "https://mattermost.com/default-report-a-problem/",
         "SupportEmail": "feedback@mattermost.com"
     },
     "AnnouncementSettings": {
@@ -292,9 +292,9 @@
         "LoginButtonTextColor": ""
     },
     "NativeAppSettings": {
-        "AppDownloadLink": "https://about.mattermost.com/downloads/",
-        "AndroidAppDownloadLink": "https://about.mattermost.com/mattermost-android-app/",
-        "IosAppDownloadLink": "https://about.mattermost.com/mattermost-ios-app/"
+        "AppDownloadLink": "https://mattermost.com/download/",
+        "AndroidAppDownloadLink": "https://mattermost.com/mattermost-android-app/",
+        "IosAppDownloadLink": "https://mattermost.com/mattermost-ios-app/"
     },
     "ClusterSettings": {
         "Enable": false,