We currently have support for a3_offset and a3_time_to_trigger only, while
there is also a3_hysteresis plus at least a1_*, a2_* and probably other parameters.

Simple A3-only based meas_config tuning might be appropriate for ORS, but for
generic enb it is better to expose full control which I do not currently feel
good to implement right now. So do not expose it at all on generic to avoid
establishing a public API yet.

enb.jinja2.cfg already has corresponding comments:

  {#  TODO fully expose lte meas_config_desc in generic SR #}
    meas_config_desc: {
    ...

  {#  TODO fully expose nr meas_config_desc in generic SR #}
    meas_config_desc: {