External codehash endpoint

[bogdan-rosianu]

Description of the reasoning behind the pull request (what feature was missing / how the problem was manifesting itself / what was the motive behind the refactoring)

• second version of the Add code-hash endpoint to address group #4391 (from an repo's internal branch)

Proposed Changes

• Add a code-hash endpoint to the address group.

Testing procedure

• call the endpoint <node-url>:<node-port>/address/erd1.../code-hash by using a SC address and it should return the same hash as the one from the <node-url>:<node-port>/address/erd1... endpoint

[gabi-vuls]

System test passed.
Scenario passed.