add karvel cli tools

[gberche-orange]

expected behavior

as a paas-templates author

• in order to use vendir and other carvel tolls (kapp)
• I need the karvel tools available at https://carvel.dev/install.sh documented from https://carvel.dev/vendir/docs/latest/install/

observed behavior

only vendir is available

e.g. imgpkg is missing