cli: Use metaprogramming to generate code during runtime when new apis sync

- Fixes metaprogramming to inject methods during shell class object's runtime
- This enable new apis that are synced to come up with new verbs, docs etc.
- Fixes printing issue
- Fixes null bitfield parsing issue

Signed-off-by: Rohit Yadav <bhaisaab@apache.org>
(cherry picked from commit a2e89c42006d41fc7fd817664e89db80d76d4bb0)

Signed-off-by: Rohit Yadav <bhaisaab@apache.org>