VHDL refactoring

There is an existing wealth of TPM and asociated FPGA firmware and supporting software already in existence which have been devloped and sucessfully tested on the AAVS platform. The challenge is that this material is not necessarily all compatible with what is required by the SKA and more specifically interacting with MCCS. This feature aimed to address this by allowing time to review key areas of the existing VHDL code and where necessary refactor and update it so that it may be used in the SKA TPM firmware and interface with MCCS as desired. During PI11 the following activities have been reviewed and refactored: 1. Refactor IO-ring to enable a single 40G interface 2. Review truncation and clipping in the signal chain 3. Remove stale/not used code from VHDL repository 4. Analiysis of the use of the current VHDL library As a result of this feature's activitie the following repository has been created and will continue to be populated through future PIs: https://www.ict.inaf.it/gitlab/SKA/ska_lfaa_firmware/-/merge_requests/30