Implementing default value support for field values

[findolor]

Motivation

See issue: #1368

Solution

• Add an optional default field to field value definitions in gui yaml
• Update getAllFieldDefinitions function to work with default filter parameter
• Update UI to show field definitions with default value under the advanced options section
• Set input value to default value in field definition if default exist
• During calldata generation, save default value if no input is entered by the user
• Update tests

Checks

By submitting this for review, I'm confirming I've done the following:

• made this PR as small as possible
• unit-tested any new functionality
• linked any relevant issues or PRs
• included screenshots (if this involves a front-end change)