AP_Proximity: add RPLidarC1 support

[rmackay9]

This adds support for the RPLidar C1 based on development and discussion here.

The datasheet says the lidar has a "low blind range of 0.05m" so the 0.2m minimum is slightly conservative but consistent with other RPLidar.

[amilcarlucas]

We should point users that want to add support for new RPlidar models to this PR!

Binary Name      Text [B]       Data [B]     BSS (B)        Total Flash Change [B] (%)      Flash Free After PR (B)
---------------  -------------  -----------  -------------  ----------------------------  -------------------------
arducopter       28 (+0.0016%)  0 (0.0000%)  -4 (-0.0015%)  28 (+0.0016%)                                    190284
arduplane        0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      190956
antennatracker   0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      642176
arducopter-heli  28 (+0.0016%)  0 (0.0000%)  -4 (-0.0015%)  28 (+0.0016%)                                    183852
ardurover        28 (+0.0017%)  0 (0.0000%)  -4 (-0.0015%)  28 (+0.0017%)                                    335168
ardusub          0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      396268
blimp            0 (0.0000%)    0 (0.0000%)  0 (0.0000%)    0 (0.0000%)                                      619492

[rmackay9]

We don't yet have confirmation that the change works but I've marked this for next week's dev call just so we don't forget about it.

[rmackay9]

This has been tested now so ready to merge I think https://discuss.ardupilot.org/t/rplidar-c1-has-different-results-in-firmware-copter-4-5-and-copter-4-4/114466/15

[rmackay9]

I've rebased on master and adjusted the maximum to 12m to match the datasheet.

[edykiro]

Hello everyone,
I'm using a RPLIDAR C1 with a Pixhawk 2.4.8. I'm having serious issues with the ACRO mode. When the LiDar is working, ACRO mode is out of control, inputting random throttle directives. When ACRO mode is working, the LiDar doesen't work properly. By tuning SCHED_LOOP_RATE, we've managed to either make the LiDar work properly, or Acro mode. But when one works, the other stops operating properly. This has been observed when modifying SCHED_LOOP_RATE from 50 Hz through 400 Hz. I'm wondering if anyone has gotten this issue, any extra data needed will be provided.