[Tech]: XCM Fee Management

[N1ghtStorm]

Problem statement

• For each incoming XCM message the parachain takes some fees on assets and burns some of them (value in units needed to execute transaction)
• Since the parachain has not any tokenomics there are two ways to organize the transaction fee withdrawal 1) Calculate the rate of each asset on the parachain and take some fees based on that. The fees would be sent to outbound channel to technical account or other treasury account or an entity 2) Calculate the rate of each asset on Sora network.

The second way is more relevant because it is easier to organize the asset rate calculation on sora side. Bit the biggest drawback of that way - is to leave parachain without transaction fees that leads to security vulnerability. Thus, parachain should have a protection from spamming with low amounts of tokens - so for each registered asset the minimum amount that can be passed through the bridge should exist.

Description

No response

Definition of Done

1. Create a storage that keeps the information about minimum amount of assets that can be sent to it via XCM
2. Create a code that checks for this amount and returns an error for each amount
3. Disable fee collection for incoming XCM messages

Requirements

No response

[N1ghtStorm]

Sora2-common pr https://github.com/sora-xor/sora2-common/pull/50