Peculiarities in Survey (Grid) Tool

#### Issue details
Not sure if I should make all these separate issues as they all relate to similar things ?

When using Auto WP => Survey (Grid) I wish to fly the typical lawnmower pattern but without triggering a camera. Would it be possible to have a Trigger Method of "None" so no messages are inserted in the flight plan please ? This will make the Flight Plan shorter and easier to check.

We would like very closely spaced rows, like 1 metre apart. Every time I type this value in Grid Options => Distance Between Lines (m) it gets changed back to the value calculated using the camera properties and does not stay set. Very annoying ! Can this be changed, maybe by including a "special" camera ?

I tried to trick it by creating a camera with a very long focal lens, say 300mm to give me closely spaced lines. Unfortunately every time I type this it gets changed back to a maximum of 180mm. Please increase this maximum focal length so we can use it as a work around.

I am trying to make quite a small survey area. I can zoom in a lot to place my Polygon points in Flight Planner but when I select Survey (Grid) the maximum zoom is much less. This makes it nearly impossible to see what is going in planned flight. Please allow a higher level of zoom.

Thanks a lot,
Jag

#### Version
1.3.50 and 1.3.49 but presumably earlier ones as well

#### Platform
[ X ] All
[ ] AntennaTracker
[ ] Copter
[ ] Plane
[ ] Rover
[ ] Sub

#### Airframe type
Not applicable

#### Hardware type
Not applicable

#### Logs
Not applicable

Start in Mission Planner's Auto WP => Survey (Grid), Grid Options, and Flight Planner UI. Review how trigger methods, distance between lines, focal length limits, and map zoom are currently handled. Done would require addressing the four requested Survey (Grid) behaviors and verifying that existing flight-plan planning remains usable.

Written by the indexing model from the issue text.