Fix miscellaneous bugs and enhance colors

[Zetison]

This PR fixes several bugs:

• Fix bug that resulted in arbitrary evaluated lat-lon coordinates for children of Areas due to the arbitrary default radius of 1.0 if not provided by the design .yml input files. The bug is resolved by first computing minimal distance between areas and letting the new radius be a third of this distance.
• Fix issue when the transmissions/links is not properly defined (e.g., from or to objects not sharing resource).
• Fix missing investments in transmission modes in the Investment overview.

Also, more colors are added for resource aliases.

[JulStraus]

Not commenting on the changes, but I think we should include the bugfixes as well for a version 0.6.x, and hence, EnergyModelsBase v0.9. Once this one is merged, I can do a cherry-pick to create said release. I created branch release-0.6 branch for this.

To this end, let me know when this branch is ready to be merged. I also have to register it at that stage.

[dqpinel]

Only a minor comment on adding more syntaxes to colors.yml