Council members are currently exclusively employees of Integritee AG. They act and vote in their role for the company. One of the councillors has left the company and shall be replaced by a new employee

Schedule a majority-carries referendum to be tabled next once it is legal to schedule
an external referendum.

The dispatch of this call must be `ExternalMajorityOrigin`.

- `proposal_hash`: The preimage hash of the proposal.

Unlike `external_propose`, blacklisting has no effect on this and it may replace a
pre-scheduled `external_propose` call.

Weight: `O(1)`

Set the collective's membership.

- `new_members`: The new member list. Be nice to the chain and provide it sorted.
- `prime`: The prime member whose vote sets the default.
- `old_count`: The upper bound for the previous number of members in storage. Used for
  weight estimation.

Requires root origin.

NOTE: Does not enforce the expected `MaxMembers` limit on the amount of members, but
      the weight estimations rely on it to estimate dispatchable weight.

# WARNING:

The `pallet-collective` can also be managed by logic outside of the pallet through the
implementation of the trait [`ChangeMembers`].
Any call to `set_members` must be careful that the member set doesn't get out of sync
with other logic managing the member set.

# <weight>
## Weight
- `O(MP + N)` where:
  - `M` old-members-count (code- and governance-bounded)
  - `N` new-members-count (code- and governance-bounded)
  - `P` proposals-count (code-bounded)
- DB:
  - 1 storage mutation (codec `O(M)` read, `O(N)` write) for reading and writing the
    members
  - 1 storage read (codec `O(P)`) for reading the proposals
  - `P` storage mutations (codec `O(M)`) for updating the votes for each proposal
  - 1 storage write (codec `O(1)`) for deleting the old `prime` and setting the new one
# </weight>

- Council members work for a company called Integritee AG.
- They have a job to act and vote for the company.
- One council member left the company and needs to be replaced.
- A new employee will be chosen to take their place.
- The council is important for making decisions for the company.

#16 Replace one council member

No Active Proposals