Schema for Custom Signatures, Improved File Formats Schema, and Dynamic Schema Tests

[MatteoCampinoti94]

Custom Signatures

• Added custom_signatures.schema.json to control structure of custom_signatures.json
• Ensures that eof and bof can either be set alone (XOR), or requires operator if they are both set

File Formats

• Require that the property of an action be set if the action property is set to it (i.e., if action: convert, then the convert property is required)
• Require PUID keys to contain at least one character and can only contain letters, numbers, dashes, underscores, and slashes ([a-zA-Z0-9_/-])

Tests

• Schemata tests are now performed dynamically based on the name of schema files