Adopt Dancer2::Template::Xslate

[Peter Mottram]

Since Dancer2::Template::Xslate is marked ADOPTME, could I (SYSPETE), as
a member of the Dancer2 core team, please have first-come on this one?
GH repo will move to PerlDancer and other D2 core team will be given
co-maint.

Cheers!
SysPete