[build] Extend default configuration for non-BIOS builds

[build] Extend default configuration for non-BIOS builds

The current usage model for iPXE is that the default configuration is
relatively minimal to reduce code size, with users encouraged to build
from source if necessary to enable additional features.  This approach
is somewhat incompatible with the Secure Boot model, which by design
makes it prohibitively difficult for users to use their own compiled
binaries.  For published Secure Boot signed binaries to be useful,
they will have to already include all features that the majority of
users will need.

Extend the default configuration for EFI (and other non-BIOS
platforms) to include HTTPS support, framebuffer support, and a
selection of commands and features that are reasonably expected to be
used by large numbers of users.

The default configuration for BIOS platforms is deliberately left
unchanged, since BIOS binaries are typically subject to severe size
constraints.

Signed-off-by: Michael Brown <mcb30@ipxe.org>