AP_Mount: add topotek gimbal driver

[rmackay9]

This adds support for the Topotek gimbals and replaces #26666

This has been heavily reworked to reduced its flash size (now 6660 on CubeOrangePlus) and to make it more robust to errors.

This has been tested on real hardware including confirming that:

• angle control works
• rate control works
• camera take-picture and record-video works
• pictures and videos are recorded to the SD card with the correct date
• pictures include EXIF data including accurate location where the picture was taken

Some of the changes compared to the initial PR are:

• display firmware version to user
• switch automatically to RC control
• simplfy set-gimbal-lock
• replace use of ctime
• use unix line endings
• comment improvements

The only known issues are:

• some use of "int" and "long" (see send_location_info() and gimbal_dist_info_analyse()
• the model version is reported as "Unknown"
• during yaw rate control the gimbal always moves in "earth-frame". Once it stops rotating (e.g. user centers sticks) the gimbal does correctly maintain either earth-frame or body-frame according to the "lock" vs "follow" state. The DJI RS2/RS3 gimbals also act like this so it's not a blocker

@laozhou-fujian this builds on your PR and the single commit is now Co-authored by both of us. Can you confirm you are OK with these changes?

Size comparison

Wiki PR ArduPilot/ardupilot_wiki#6092

[Hwurzburg]

needs MNT_TYPE metadata addition

[rmackay9]

We discussed this on the dev call and the major concern was that the driver consumes far too much flash (about 9K). Various devs have given suggestions on how it could be made smaller so I will attempt to rework the driver based on this advice.

[laozhou-fujian]

Okay, I will start working on the modifications, thank you.

[rmackay9]

@laozhou-fujian,

This came up on the dev call and Tridge and I agreed that we should help make this driver smaller. I've got a 2 week vacation coming up soon but hopefully we can help.

[laozhou-fujian]

@laozhou-fujian,

This came up on the dev call and Tridge and I agreed that we should help make this driver smaller. I've got a 2 week vacation coming up soon but hopefully we can help.

Thank you for your help. I will try my best to complete it this week. Thank you.

[laozhou-fujian]

@laozhou-fujian,

This came up on the dev call and Tridge and I agreed that we should help make this driver smaller. I've got a 2 week vacation coming up soon but hopefully we can help.

Sorry, I've been very busy recently. I will finish it as soon as possible

[rmackay9]

@laozhou-fujian,

Just FYI, I've started shrinking the driver and I expect I will complete it within the next week. No need to stress, I just wanted to make sure we don't waste effort by both doing the same thing.

[laozhou-fujian]

@laozhou-fujian,

Just FYI, I've started shrinking the driver and I expect I will complete it within the next week. No need to stress, I just wanted to make sure we don't waste effort by both doing the same thing.

Thank you for your advice. I will revise it right away. I feel very sorry for having to deal with a lot of urgent things recently

Tridge's requests completed