[hardikdr]

Proposed Changes

For now, this PR adds an initial ConfigDB-based backend alongside the existing script-based backend. It's WIP.

Some open points:

• Check with @Giluerre how we can reuse or converge with the ConfigDB accessor work already done in [sonic-operator](ironcore-dev/sonic-operator@b937bfd).
• Figure out how reset should work properly. Right now, it mostly follows what the script-based backend does. Should we also reset the interfaces or any other state?
• Decide where the ConfigDB client should live: in Fabric or sonic-operator
• There may be a few more details to discuss as we test the approach more.

Feedback and ideas are very welcome.

Fixes #