[ISSUE #12614] Display the number of days to retain the configuration history dynamically on the front end

[shengbinxu]

issue: #12614

What is the purpose of the change

Display the number of days to retain the configuration history dynamically on the front end, the current value displayed on the front end is hard-coded (30 days)

Brief changelog

1. Add a field "config_retention_days": "720" to the response of the API v1/console/server/state.

2. Display the value of the variable config_retention_days on the front end.

Verifying this change

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