Gas storage fee mechanism

[moul]

Description:
Implement a system to manage storage fees for transactions by locking GNOT proportional to additional storage usage. This ensures fair accounting for storage costs and provides incentives for efficient storage use.

Details:

• Transactions that increase storage should lock GNOT from the StorageAllowance field in MsgCall/MsgRun.
• GNOT locked for storage should be calculated based on a storage price set in genesis (r/sys/params.CURRENT_STORAGE_PRICE.string), initially 1B GNOT / 10TB.
• When storage is freed, return GNOT to the caller as bytes freed / CURRENT_STORAGE_PRICE.
• The default StorageAllowance should be defined in r/sys/params as a reasonable maximum, adjustable per transaction.

Governance and Parameters:

• Storage price adjustments must be handled through governance (r/gov).
• Track total GNOT locked (LOCKED_GNOT) and total bytes stored per realm.
• Ensure LOCKED_GNOT / BYTES >= CURRENT_STORAGE_PRICE to prevent underfunding as prices decrease.

Future Consideration:

• Add SUBSIDIZED_GNOT (for each realm) to allow realms to subsidize storage costs for transactions.

Next Steps:

Open questions and suggestions in this issue before proceeding.

If possible, define pseudocode or interfaces for the mechanism before starting implementation.