feat: P4 endpoints support and several bug fixes

New features

• Support for P4 device endpoints (Closes #225 (closed) )
• Support for CloneSession entries (Closes #228 (closed))

Bug fixes

• Fix resource retrieval when resource key is meter or packet controller metadata (Closes #139 (closed))
• Fix parsing of CloneSession entries (Closes #228 (closed))
• Fix handling of table entries that only support modify() operation (Closes #227 (closed))
• Every new rule has to have a unique resource key (Closes #223 (closed) )