Framed substream default maximum frame size

[hansieodendaal]

Description

Added a maximum frame length constant for a framed substream, equal to the default Tokio setting, so it can be visible in the Tari code and not dependent on the default frame size.

Motivation and Context

Difficult to find this default setting for tuning when it is hidden away in the Tokio libraries. This will also protect the Tari code base from future Tokio code changes.

How Has This Been Tested?

Tested in a base node exe.

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)
• Feature refactor (No new feature or functional changes, but performance or technical debt improvements)
• New Tests
• Documentation

Checklist:

• I'm merging against the development branch.
• I ran cargo-fmt --all before pushing.
• I have squashed my commits into a single commit.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.

[sdbondi]

Small nits - but otherwise looks good