feat: limit permissionless generic call gas usage

[mpetrun5]

Previously, we had maxFee field for this purpose, but we didn't use and mistakenly thought we couldn't for the purpose of limiting generic call gas usage which prevented us of batching them.
This uses that value for that purpose.

Description

Related Issue Or Context

Closes: #199
Closes: #201

How Has This Been Tested? Testing details.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation

Checklist:

• I have commented my code, particularly in hard-to-understand areas.
• I have ensured that all acceptance criteria (or expected behavior) from issue are met
• I have updated the documentation locally and in chainbridge-docs.
• I have added tests to cover my changes.
• I have ensured that all the checks are passing and green, I've signed the CLA bot

[nmlinaric]

LGTM

[lastperson]

Any rationale why is it called fee and not gas ?

[mpetrun5]

Any rationale why is it called fee and not gas ?

I think it was to reference that the destination might not be Evm and to not make it specific towards that.