chore: market matching pool tidy up

[eoin-betdex]

This change updates the MarketMatchingPool account to include the data used as seeds in the data stored in the account. This should make it easy for anyone using/building on the protocol to interact with MarketMatchingPools.

This also enables the addition of getProgramAccounts queries for these accounts simplifying the fetching of interesting MarketMatchingPools.

The fields added are:

    pub market_outcome_index: u16,
    pub for_outcome: bool,
    pub price: f64,

As the seeds are stored on the account now, including the market pk, there was no longer any need to rely on validation of the seeds in the CloseMarketMatchingPool context to ensure the market was valid for the matching pool. This can now be done using a has_one constraint.

Additionally purchaser was renamed to payer to better fit convention in the protocol.

A bug was also discovered in the client query code when fields being used as filters were non-contiguous incorrect filtering would occur. This has been fixed in this PR also.