Refactor system console buttons into RequestButton component. (#6808)

Since I was going to make yet another button for the ElasticSearch test
config button, I refactored all of them to use a single common component
and tidied that component up and gave it some unit tests.

webapp/i18n/en.json

@@ -601,13 +601,20 @@
   "admin.rate.title": "Rate Limit Settings",
   "admin.recycle.button": "Recycle Database Connections",
   "admin.recycle.loading": " Recycling...",
-  "admin.recycle.recycleDescription": "Deployments using multiple databases can switch from one master database to another without restarting the Mattermost server by updating \"config.json\" to the new desired configuration and using the <a href=\"../general/configuration\"><b>Configuration > Reload Configuration from Disk</b></a> feature to load the new settings while the server is running. The administrator should then use <b>Recycle Database Connections</b> feature to recycle the database connections based on the new settings.",
+  "admin.recycle.recycleDescription": "Deployments using multiple databases can switch from one master database to another without restarting the Mattermost server by updating \"config.json\" to the new desired configuration and using the {reloadConfiguration} feature to load the new settings while the server is running. The administrator should then use {featureName} feature to recycle the database connections based on the new settings.",
+  "admin.recycle.recycleDescription.featureName": "Recycle Database Connections",
+  "admin.recycle.recycleDescription.reloadConfiguration": "Configuration > Reload Configuration from Disk",
   "admin.recycle.reloadFail": "Recycling unsuccessful: {error}",
   "admin.regenerate": "Regenerate",
   "admin.reload.button": "Reload Configuration From Disk",
   "admin.reload.loading": " Loading...",
-  "admin.reload.reloadDescription": "Deployments using multiple databases can switch from one master database to another without restarting the Mattermost server by updating \"config.json\" to the new desired configuration and using the <b>Reload Configuration from Disk</b> feature to load the new settings while the server is running. The administrator should then use the <a href=\"../advanced/database\"><b>Database > Recycle Database Connections</b></a> feature to recycle the database connections based on the new settings.",
+  "admin.reload.reloadDescription": "Deployments using multiple databases can switch from one master database to another without restarting the Mattermost server by updating \"config.json\" to the new desired configuration and using the {featureName} feature to load the new settings while the server is running. The administrator should then use the {recycleDatabaseConnections} feature to recycle the database connections based on the new settings.",
+  "admin.reload.reloadDescription.featureName": "Reload Configuration from Disk",
+  "admin.reload.reloadDescription.recycleDatabaseConnections": "Database > Recycle Database Connections",
   "admin.reload.reloadFail": "Reloading unsuccessful: {error}",
+  "admin.requestButton.loading": " Loading...",
+  "admin.requestButton.requestSuccess": "Test Successful",
+  "admin.requestButton.requestFailure": "Test Failure: {error}",
   "admin.reset_password.close": "Close",
   "admin.reset_password.newPassword": "New Password",
   "admin.reset_password.select": "Select",