Consider allowing to change node address in one step instead of removing-then-adding

[drmingdrmer]

When adding an existing node as a learner with a new address the old address remains unchanged.

There should be a way to update Node directly without removing-then-adding.
But this has risk of leading to brain split. Use it with caution.

Incorrect updating node could occur if the new address belongs to another node, leading to
two elected leaders.

Consider a 3-node cluster (a, b, c, with addresses x, y, z) and an
uninitialized node d with address w:

a: x
b: y
c: z

d: w

Allowing direct address changes (e.g., b's address from y to w) would
enable both x, y and z, w to form quorums and elect leaders.

• c proposes ChangeMembership: {a:x, b:w, c:z};

• c and d grant c;

• c elects itself as leader

• c and d confirm c as leader

• a elects itself as leader

• a and b confirm a as leader

It's best to avoid updating Node directly

[github-actions]

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