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In the current scenario, the problem discovered is that there is a time gap between group0 creation and raft_initialize_discovery_leader call. Because of that, the group0 snapshot/apply entry enters wrong values from the disk(null) and updates the in-memory variables to wrong values. During the above time gap, the in-memory variables have wrong values and perform absurd actions. This PR removes the variable `_manage_topology_change_kind_from_group0` which was used earlier as a work around for correctly handling `topology_change_kind` variable, it was brittle and had some bugs (causing issues like scylladb/scylladb#21114). The reason for this bug that _manage_topology_change_kind used to block reading from disk and was enabled after group0 initialization and starting raft server for the restart case. Similarly, it was hard to manage `topology_change_kind` using `_manage_topology_change_kind_from_group0` correctly in bug free manner. Post `_manage_topology_change_kind_from_group0` removal, careful management of `topology_change_kind` variable was needed for maintaining correct `topology_change_kind` in all scenarios. So this PR also performs a refactoring to populate all init data to system tables even before group0 creation(via `raft_initialize_discovery_leader` function). Now because `raft_initialize_discovery_leader` happens before the group 0 creation, we write mutations directly to system tables instead of a group 0 command. Hence, post group0 creation, the node can read the correct values from system tables and correct values are maintained throughout. Added a new function `initialize_done_topology_upgrade_state` which takes care of updating the correct upgrade state to system tables before starting group0 server. This ensures that the node can read the correct values from system tables and correct values are maintained throughout. By moving `raft_initialize_discovery_leader` logic to happen before starting group0 server, and not as group0 command post server start, we also get rid of the potential problem of init group0 command not being the 1st command on the server. Hence ensuring full integrity as expected by programmer. This PR fixes a bug. Hence we need to backport it. Fixes: scylladb/scylladb#21114 Closes scylladb/scylladb#22484 * https://github.com/scylladb/scylladb: storage_service: Remove the variable _manage_topology_change_kind_from_group0 storage_service: fix indentation after the previous commit raft topology: Add support for raft topology system tables initialization to happen before group0 initialization service/raft: Refactor mutation writing helper functions.