Add Democracy pallet to the Mythical runtime

[valentinfernandez1]

This draft PR introduces Democracy to the Mythical chain using pallet-democracy. Given that Democracy has access to permissioned processes within the runtime , confirmation from the Mythical team is required regarding the key parameters before proceeding. This ensures that all governance-related settings align with their specific requirements.

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Pending Parameter Confirmations

Democracy pallet

• LaunchPeriod: How often new public referenda are launched.
• VotingPeriod: How often votes for referenda are tallied.
• FastTrackVotingPeriod: The minimum voting period for a fast-tracked referendum.
• MinimumDeposit: The minimum amount to be used as a deposit for a public referendum proposal.
• Enactment Period: The minimum period for locking funds and the period between a proposal being approved and enacted.
• CooloffPeriod: The period in blocks where a proposal may not be re-submitted after being vetoed.
• SubmitOrigin: Origin from which the new proposal can be made.
• FastTrackOrigin: Origin that can call to make an externally proposed proposal that is "majority-carries" become a referendum immediately.
• CancellationOrigin: Origin from which any referendum may be cancelled in an emergency.
• BlacklistOrigin: Origin from which proposals may be blacklisted.
• CancelProposalOrigin: Origin from which a proposal may be cancelled and its backers slashed.
• VetoOrigin: Origin for anyone able to veto proposals.
• Slash: How to handle the funds slashed. E.g. Deposit them into the treasury.

Treasury pallet

• SpendPeriod: Period between successive spends.
• TreasuryPalletId: The treasury's pallet id, used for deriving its sovereign account ID.
• MaxApprovals: The maximum number of approvals that can wait in the spending queue.
• SpendPayoutPeriod: The period during which an approved treasury spend has to be claimed.
• SpendOrigin: The origin required for approving spends from the treasury outside of the proposal process.
• MaxBalance: The maximum amount in a native asset that the SpendOrigin is allowed to spend at a time.

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Next Steps:

Each parameter has been flagged with //TODO: Pending confirmation in the code. Once the Mythical team provides the final values, we will update this draft and proceed with creating a full PR.

If any adjustments are necessary, please leave a comment directly on this PR with the requested values.

cc @cthacker