Insert irrigate/plant/... orders in goto mode

[lmoureaux]

Is your feature request related to a problem? Please describe.
The goto implementation has been changed to be more in line with the actions system. It now works with actions directly instead of retrofitting them into a path. This lead to improved results with rulesets like Aviation.

However in the process we lost the "connect with..." functionality, #889. This used the goto code with custom cost functions optimized for laying out roads (minimizing distance), rails (minimizing build time), or irrigation (also build time). Underlying extras were automatically added if needed (e.g. roads before rails and irrigation before farmland).

Describe the solution you'd like
I propose the following behavior while in goto mode:

• Hitting R introduces a Build Road waypoint at the mouse location and a Build Road action is inserted into the orders list
• The turn counter takes the completion time into account
• Hitting ESC deletes the last waypoint including any order given

Sprites should be drawn to indicate the build target.

Optionally check already-planned orders for the current tile and take them into account to allow building farmland and irrigation in one go.

Describe alternatives you've considered
Re-establishing a similar cost-based approach as before. It is less flexible but may be easier-to-use.

Another solver could be created where you select workers and paint an area to be filled with, say, irrigation. Unfortunately taking promotions into account in the orders system is difficult, so this would work best with autoworkers.

Additional context
@ec429 you said you were using "connect with" before, would this approach work for you?