-Enabled this model in tb_apertif_unb1_fn_beamformer_tp_bg.

- Switched fail and ok in reg map
- Removed comments  

Removed internal DDR memory model (now needs to be instantiated in tb). Use dedicated records for DDR3 and DDR4 phy interfaces, instead of the combined record.

Renamed ctlr_mosi into ctlr_tech_mosi for the technology IP side to more clearly distinghuis it from ctrl_drv_mosi for the IO driver side.

splitted the terminationcontrol lines from the record types 't_tech_ddr_phy_in' and 't_tech_ddr_phy_ou'

Use g_rd_fifo_af_margin to fit one (DDR3 IP) or more (DDR4 IP) rd burst accesses of g_tech_ddr.maxburstsize each.

Added g_sim, when TRUE then use internal DDR memory model in tech_ddr component. When FALSE use DDR memory model in test bench.

Define t_mem_ctlr_mosi/miso in common_mem_pkg, to use that instead of the records defined in tech_ddr_pkg. Also remove t_tech_ddr_addr record because it is not needed.

Added io_ddr_cross_domain.vhd to handle dvr_clk and ctlr_clk domains in case they are different clock domains.

Redefined write flush modes. Now the flush is still under control by dvr_flush_en, and disabled when kept tied to '0'.