feat: export methods for encoding/decoding dataSourceWithHash and valueContent

[CJ42]

What kind of change does this PR introduce (bug fix, feature, docs update, ...)?

⭐

What is the current behaviour (you can also link to an open issue here)?

Currently, there are no methods available in the ERC725 class for:

• encoding / decoding value Content
• encoding / decoding JSONURL or VerifiableURI

This is useful for tools like ERC725-inspect, lsp-utils, or services like indexers to easily decode data from logs / fetched from contracts, or prepare data easily without requiring a full schema.

What is the new behaviour (if this is a feature change)?

Add the following methods:

• encodeDataSourceWithHash(...)
• decodeDataSourceWithHash(...)
• encodeValueContent(...)
• decodeValueContent(...)

available to be imported individually like this:

import { encodeDataSourceWithHash } from "@erc725/erc725.js"

or from the ERC725 class (as static methods or accessible in an instance).

Other information: