Add acquisition helper methods

[kkostov]

This PR addresses #72 by adding Acquisition related helpers:

/**
 * Send a `TelemetryDeck.Acquisition.userAcquired` signal with the provided channel.
 */
fun acquiredUser(channel: String,...)

/**
 * Send a `TelemetryDeck.Acquisition.leadStarted` signal with the provided leadId.
 */
fun leadStarted(leadId: String,...)

/**
 * Send a `TelemetryDeck.Acquisition.leadConverted` signal with the provided leadId.
 */
fun leadConverted(leadId: String,...)

[winsmith]

Muy bien!