This commit adds support for pensando asic called ELBA. ELBA is used in pci based cards and in smartswitches.
#### Why I did it
This commit introduces pensando platform which is based on ELBA ASIC.
##### Work item tracking
- Microsoft ADO **(number only)**:
#### How I did it
Created platform/pensando folder and created makefiles specific to pensando.
This mainly creates pensando docker (which OEM's need to download before building an image) which has all the userspace to initialize and use the DPU (ELBA ASIC).
Output of the build process creates two images which can be used from ONIE and goldfw.
Recommendation is use to use ONIE.
#### How to verify it
Load the SONiC image via ONIE or goldfw and make sure the interfaces are UP.
##### Description for the changelog
Add pensando platform support.
