pallet-treasury cleanup

[Dinonard]

Pull Request Summary

Removes unused calls & types from pallet-treasury.
These calls were incorrectly used in our governance and it's better to remove them (they don't work anyways).

If ever in the future we need these calls, the right action is to delete our fork & use the regular pallet-treasury from the polkadot-sdk.

[github-actions]

Package	Line Rate	Branch Rate	Health
precompiles/sr25519/src	56%	0%	➖
chain-extensions/types/assets/src	0%	0%	❌
pallets/astar-xcm-benchmarks/src/fungible	100%	0%	✔
pallets/dynamic-evm-base-fee/src	84%	0%	✔
precompiles/dapp-staking/src/test	0%	0%	❌
pallets/astar-xcm-benchmarks/src/generic	100%	0%	✔
pallets/dapp-staking/rpc/runtime-api/src	0%	0%	❌
pallets/dapp-staking/src/benchmarking	94%	0%	✔
chain-extensions/types/unified-accounts/src	0%	0%	❌
pallets/dapp-staking/src/test	0%	0%	❌
primitives/src	54%	0%	➖
pallets/ethereum-checked/src	76%	0%	➖
pallets/price-aggregator/src	75%	0%	➖
pallets/xc-asset-config/src	48%	0%	❌
precompiles/dispatch-lockdrop/src	83%	0%	✔
pallets/unified-accounts/src	81%	0%	✔
pallets/vesting-mbm/src	87%	0%	✔
pallets/static-price-provider/src	91%	0%	✔
pallets/dapp-staking/src	79%	0%	➖
precompiles/dapp-staking/src	89%	0%	✔
chain-extensions/unified-accounts/src	0%	0%	❌
primitives/src/xcm	62%	0%	➖
precompiles/assets-erc20/src	78%	0%	➖
pallets/astar-xcm-benchmarks/src	86%	0%	✔
pallets/inflation/src	90%	0%	✔
pallets/collective-proxy/src	94%	0%	✔
precompiles/substrate-ecdsa/src	67%	0%	➖
precompiles/unified-accounts/src	100%	0%	✔
precompiles/xcm/src	69%	0%	➖
pallets/collator-selection/src	87%	0%	✔
chain-extensions/pallet-assets/src	54%	0%	➖
Summary	76% (3484 / 4605)	0% (0 / 0)	➖

Minimum allowed line rate is 50%

[grbIzl]

Sorry. I didn't get it. From the code it looks like you removed all API methods from the pallet (please correct me if I'm wrong). Is anything left? What's the purpose of leftovers? Can we just drop the whole pallet?

[Dinonard]

Sorry. I didn't get it. From the code it looks like you removed all API methods from the pallet (please correct me if I'm wrong). Is anything left? What's the purpose of leftovers? Can we just drop the whole pallet?

I've removed the calls that are part of new treasury API, which we don't use.
Not everything has been deleted, the only 3 extrinsics we use have been kept.

We cannot drop the whole pallet, it's part of the governance system.