Add extensions for getting all data kinds of a Contact or RawContact as a list

[vestrel00]

Problem

Currently, in order for users of this library to gather all of the DataEntity belonging to a RawContact (or all of the RawContacts belonging to a Contact), they would have to manually build that list... It might look something like this,

val rawContactData = buildList<ExistingDataEntity> {
    addAll(rawContact.addresses)
    addAll(rawContact.emails)
    addAll(rawContact.events)
    // and so on...
}

Gathering all data in a single list may be useful in some cases such as #306 or contacts.core.data.Data APIs.

Solution

Implement and provide extension functions for library users so they don't have to!

• Update relevant docs (about-api-entities.md, convenience-functions.md)
• Update gh-pages

[vestrel00]

🔥 🔥 🔥 🔥 🔥 🔥 🔥 🔥
This is now release in 0.3.1!
🔥 🔥 🔥 🔥 🔥 🔥 🔥 🔥