Better return values

[gfrn]

• [x] get_scope_vars should return a dict with the same data as before instead of printing to stdout
• [x] Same for get_wfmref_vars
• [x] Same for read_udc_version
• [x] Same for write_wfmref
• [x] Same for read_vars_fbp
• [x] Same for read_vars_common
• [x] Same for get_siggen_vars
• [x] read_bsmp_variable_gen prints the same content that it returns, should remove redundant print
• [x] Same for read_vars_fbp
• [x] Same for decode_interlocks
• [x] Same for read_vars_fbp_dclink
• [x] Same for read_vars_fac_acdc
• [x] Same for read_vars_fac_dcdc
• [x] Same for read_vars_fac_dcdc_ema
• [x] Same for read_vars_fac_2s_acdc
• [x] Same for read_vars_fac_2s_dcdc
• [x] Same for read_vars_fac_2p4s_dcdc
• [x] Same for read_vars_fap
• [x] Same for read_vars_fap_4p
• [x] Same for read_vars_fap_2p2s
• [x] Same for read_vars_fap_225A
• [x] Same for read_vars_fac_2p_acdc_imas
• [x] Same for read_vars_fac_2p_dcdc_imas
• [x] Same for check_param_bank
• [x] Same for read_vars_fac_n
• [x] Same for calc_pi
• [x] Same for get_param_bank
• [x] Same for get_dsp_modules_bank