Introduce order protection + Improved processing of the webhook

[BitcoinMitchell]

Questions	Answers
Description	- Introduces order protection similar to what the woocommerce plugin has. - Added payment to order for settled payments. - Improved overall processing of an order. - DX: Adds a simple bitcoin-cli.sh-script to interact with the bitcoind defined in the docker-compose.
Type	improvement
BC breaks	no
Deprecations	no
Fixes	#94
Depends on	- #93 - #95
How to test	- Mark an order as paid in the backend, mark the invoice as invalid in BTCPayServer. The order state will stay the same and a message will be added. - For every settled payment, a payment should be added to the order. - Re-triggering an InvoicePaymentSettled-webhook should not add an additional payment.

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[ndeet]

Nice work and refactor, much cleaner and nice feature of the order protection 👍

Only a few nitpicks, feel free to ignore.

[BitcoinMitchell]

Nice work and refactor, much cleaner and nice feature of the order protection 👍

Only a few nitpicks, feel free to ignore.

Thank you, I'll create PRs for the the nitpicks that I will merge into this PR, before I merge this entire PR into master.

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I've noticed that maybe we are adding too many messages, will rethink that as well.

[ndeet]

Tested several use cases, partial payments, manually settled/invalid, expired, overpayment

Looks all good and with nice warning in case of unusual flow e.g. manually setting paid and then getting an expired / manually marked invalid webhook

Nice work 👍

[BitcoinMitchell]

Tested several use cases, partial payments, manually settled/invalid, expired, overpayment

Looks all good and with nice warning in case of unusual flow e.g. manually setting paid and then getting an expired / manually marked invalid webhook

Nice work 👍

Awesome, glad to hear it all worked smoothly. The only thing I wanna double check now is different currencies (since I do value * rate for the payment). If that also works as expected, I'll merge and release this :)

[ndeet]

LGTM!