Update makefile targets

[boris]

This pull request adds support for customizing transaction gas and fee parameters in the Makefile for Ethereum smart contract operations. The main improvement is the introduction of new environment variables and logic to allow users to specify gas limit, max fee, and priority fee for relevant contract interactions.

Transaction fee customization:

• Introduced new environment variables: TX_GAS_LIMIT, TX_MAX_FEE, and TX_PRIORITY_FEE to allow users to set custom values for transaction gas and fees.
• Added the TX_FEE_OPTS variable, which conditionally includes the appropriate command-line flags for cast send based on the provided environment variables.

Integration with contract commands:

• Updated the send target to include $(TX_FEE_OPTS), enabling custom gas and fee options when sending CLPc tokens.
• Updated the claim-direct target to include $(TX_FEE_OPTS), allowing users to customize gas and fee options when claiming tokens directly.