Add shres utility to create shared resources images for SYSPART #227
Description
Is your feature request related to a problem? Please describe.
The new shared resource area in the system partition requires a tool to put files into it.
Describe the solution you'd like
A utility called shres that creates these images.
Describe alternatives you've considered
Native utility on MEGA65. Should be done at some point, but too time consuming right now, especially since the tool needs to support files that are hundreds of megabytes in size.
Additional context
Required for MEGAphone Unicode font support