QoE Metrics Reporting - Support for Playlist metric

[dsilhavy]

Feature description
The playlist metric should be derived by the ExoPlayerListener class and included in the QoE metrics report

Relevant specifications and corresponding sections

• 3GPP TS 26.501 Rel-17
• 3GPP TS 26.512 Rel-17
• 3GPP TS 26.247 - clause 10.2.7

Additional context
XSD Definition

<xs:element name="PlayList" type="PlayListType"/>

<xs:complexType name="PlayListType">
    <xs:choice>
        <xs:element name="Trace" maxOccurs="unbounded" type="PlayListEntryType" />
    </xs:choice>
    <xs:anyAttribute processContents="skip" />
</xs:complexType><xs:complexType name="PlayListEntryType">
<xs:choice>
    <xs:element name="TraceEntry" maxOccurs="unbounded" type="PlayListTraceEntryType" />
</xs:choice>
<xs:attribute name="start" type="xs:dateTime" use="required" />
<xs:attribute name="mstart" type="xs:duration" use="required" />
<xs:attribute name="startType" type="StartType" use="required" />
<xs:anyAttribute processContents="skip" />
</xs:complexType>

<xs:complexType name="PlayListTraceEntryType">
<xs:attribute name="representationId" type="xs:string" use="optional" />
<xs:attribute name="subrepLevel" type="xs:unsignedInt" use="optional" />
<xs:attribute name="start" type="xs:dateTime" use="required" />
<xs:attribute name="sstart" type="xs:duration" use="required" />
<xs:attribute name="duration" type="xs:unsignedInt" use="required" />
<xs:attribute name="playbackSpeed" type="xs:double" use="optional" />
<xs:attribute name="stopReason" type="StopReasonType" use="optional" />
<xs:attribute name="stopReasonOther" type="xs:string" use="optional" />
<xs:anyAttribute processContents="skip" />
</xs:complexType>