package_manager.py: set preferred ABI for rpm

package_manager.py: set preferred ABI for rpm

When using the RPM packaging backend to generate a rootfs there needs to
be a way to configure the preferred ABI to resolve ELF file conflicts.

Currently RPM resolves ELF file conflicts with the last-installed wins.
Using SMART it's difficult to know what the last installed will be.

There are three specific policies that can be selected:
1: ELF32 wins
2: ELF64 wins
3: ELF64 N32 wins (mips64 or mips64el only)

Another option "0" is uncontrollable, which means that if two are being
installed at once Elf64 is preferred, but if they're being installed in
two different transactions, last in wins, so we don't document it.

Add RPM_PREFER_COLOR to let the user config the preferred ABI.

[YOCTO #4073]

(From OE-Core rev: f56d7be2c35cedcd763ba66913982aa4c425d561)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>