Support beacon_klipper version >= 2.0.0, a.k.a Beacon Contact

[crkochan]

My initial take on fixing #636.

Beacon Contact introduced code in their BeaconHomingHelper class that specifically balks when [homing_override] is present in the Klipper config.

My attempt at working around this was to...

• Create a separate beacon_contact.cfg in the hardware probes folder
• Specify beacon_contact as variable_probe_type_enabled to be used by future g-code conditionals
• Update machine.cfg so that homing_override.cfg is not always included
• Move the homing_override.cfg include into generic_probe.cfg base macro so that every other probe can still get it

There are still a couple more changes I want to make based on the Beacon documentation that are centered on the start_print macro, but I'm opening this as a draft PR so that I can also include any feedback, since this is my first contribution.

[ksummers92]

I tried your implementation and there are some default values that are not included that causes an error "Option 'home_method' is not valid in section 'beacon'". This is likely due to home_xy_position not being defined by some kind of defaults. Probably best to retrieve the zero reference position/bed center like the homing_override.cfg does and assume that as the home_xy_position.

[crkochan]

I started working on this PR after I already had Beacon more or less up and running, so you're right, I already had home_xy_position defined in my overrides.cfg file.

Unfortunately, the value needs to be defined outside of a gcode macro, so I can't use the same trick that homing_override.cfg does.

I'm not quite sure what the optimal solution is. I can add the documented recommended defaults into beacon_contact.cfg, and pick a set of coordinates that are not totally outlandish for a Voron Trident or V2, but that might not fly for users of other printers.

Maybe that, plus adding a commented beacon block to the user_templates overrides.cfg, basically some way of signaling that for contact, a user is probably going to want to have some sort of config override setup.

Just to share, this is my beacon block present in overrides.cfg.

[beacon]
serial: /dev/serial/by-id/usb-Beacon_Beacon_RevH_9AA5D66B5154354D38202020FF0A0B36-if00
x_offset: 0
y_offset: 26.5
mesh_main_direction: x
mesh_runs: 2
accel_axes_map: x, y, z
home_xy_position: 150, 150
home_z_hop: 5
home_z_hop_speed: 30
home_xy_move_speed: 300
autocal_speed: 5
home_method: proximity
home_method_when_homed: proximity
home_autocalibrate: never