SVGHMI: Implemented "Add Font" and "Remove Font", add font embedding in CSS at build time, tested ok with some OTF for now.
<xsd:element name="Xenomai">
<xsd:complexType>
%(toolchain_gcc)s
<xsd:attribute name="XenoConfig" type="xsd:string" use="optional" default="xeno-config"/>
</xsd:complexType>
</xsd:element>