boot/uboot: add BR2_TARGET_UBOOT_USE_BINMAN option

boot/uboot: add BR2_TARGET_UBOOT_USE_BINMAN option

Recent version of U-Boot use binman to provide a mechanism for building
images, from simple SPL + U-Boot combinations, to more complex
arrangements with many parts.

This tool uses additional host python modules that must be provided by
Buildroot. So introduce a new option BR2_TARGET_UBOOT_USE_BINMAN to
add additional host packages in U-Boot build dependency to use binman.

The binman requirement is directly included in buildman dependency
(tools/buildman/requirements.txt) since within U-Boot, binman is
invoked by the build system, here buildman [1].

[1] https://docs.u-boot.org/en/v2024.01/develop/package/binman.html#invoking-binman-within-u-boot

Co-developed-by: Romain Naour <[email protected]>
Signed-off-by: Dario Binacchi <[email protected]>
Signed-off-by: Romain Naour <[email protected]>
Signed-off-by: Arnout Vandecappelle <[email protected]>