schema freshness metric

[Satbek]

Add a gauge metric that checks whether the schema matches the Tarantool version. If it matches, set to 1; if not, set to 0.

How to check schema:
https://github.com/tarantool/tarantool/blob/03048fa79c1133e6b77603639a240e36d724c92e/src/box/lua/config/applier/box_status.lua#L29C1-L37C4

local function is_schema_outdated()
    local current_version = box.internal.dd_version()
    local latest_version = box.internal.latest_dd_version()
    return current_version < latest_version
end

[Satbek]

also we can check schema freshness via alrert https://github.com/tarantool/tarantool/blob/03048fa79c1133e6b77603639a240e36d724c92e/src/box/lua/config/applier/box_status.lua#L5C35-L5C61