Addresses #3734

A few notes about how the integration was done:

Events:

The only event emitted by content pallet w.r.t. creator tokens is CreatorTokenIssued, since this is the only event needed in order for the query node to be able to connect a creator token with a given channel. All other events are emitted from project_token pallet (some missing events were added: TokenSaleInitialized, UpcomingTokenSaleUpdated, TransferPolicyChangedToPermissionless)

Deriving member context:

get_worker_member_id method was added to WorkingGroupAuthenticator, allowing the content pallet to derive the member_id based on ContentActor context through a new function called get_member_id_of_actor:

This function is used to determine:

• CRT source account for creator token sale (init_creator_token_sale)
• CRT patronage destination (claim_creator_token_patronage_credit)
• CRT source account for issuer transfer (creator_token_issuer_transfer)

Token sale JOY earnings

A new earnings_destination field was added to TokenSale, which is Option<AccountId> and works as follows:

• If earnings_destination.is_some() - JOY earnings from the sale (minus platform fee) are sent to earnings_destination account
• If earnings_destination.is_none() - all JOY earnings from the sale are burned

The content pallet fills this field based on the channel owner:

• If ChannelOwner is Member: earnings_destination is Some(member_controller_account)
• If ChannelOwner is CuratorGroup: earnings_destination is None

Curator channels

Following #3784, there were a few other curator-channel-specific features implemented:

• auto_finalize field was added to TokenSale, which controls whether the sale is automatically removed when quantity_left == 0. Content pallet sets this field to true if ChannelOwner is Member and false if ChannelOwner is CuratorGroup.
• recover_unsold_tokens extrinsic was replaced with finalize_token_sale method, which is callable only by channel owner through content pallet and returns the total amount of JOY collected during the sale (funds_collected). Additionally, if ChannelOwner is CuratorGroup, the content pallet then adds funds_collected to the Council Budget
• claim_creator_token_patronage_credit was blocked for curator-owned channels

Bloat bonds

Some code in project_token pallet was changed so that the bloat_bond is always paid by the sender of content extrinsic (in case the interaction with project_token pallet happens through content pallet). This means:

• Member controller account in case ChannelOwner is Member
• Curator's role account in case ChannelOwner is Curator

Tests:

I limited the scope of the tests to errors / events / state changes coming directly from content pallet, as we have a separate set of tests for project_token pallet. This can be improved in the future, but I suggest it to be done outside of the scope of this PR, as it's already quite large.

Types and ProjectToken trait:

pallet_token's trait.rs and types.rs were exposed and some types were made public (pub(crate) -> pub), I also slightly modified the ProjectToken trait to make it easier for the content module to use it.