added navcon files

[sweet235]

I added a few manual navigation connections, most noticably down from the pipes in the default alien base (a natural place to build eggs at) and down from the cavity in the central room (where humans build occasionally). A few other connections are from crates to the floor.

[sweet235]

Disclaimer: I am not sure if the map package is a good place for these files. Maybe we can clarify where these files should go if they go into a release version.

Edit:
On IRC, I said this:

<Sweet0> however, i am not convinced that the map repo is the proper place for these files
<Sweet0> especially if we are going to remove navmesh files from map packages
<Sweet0> then it does not seem sensible to have other bot files there
<Sweet0> also, changing the bot code might require changes to the navcons (they work with current bot code)
<Sweet0> so it would seem awkwardly complicated to have to change the map package once the bot code changes in an impactful way

[illwieckz]

Navcon in map package looks fine to me, we can see them as part of the map source.

Though, we may want a diffable format: Unvanquished/Unvanquished#1772

[sweet235]

Converted to draft until I feel we reached unanimous consenus.

[ghost]

ping

[ghost]

obsolete, we now use text-based format?

[illwieckz]

Some navcons already have been merged, but there may be updates to merge.