Improve LoD11 fallback/skip mechanism + timeout

[Ylannl]

For the roofer CLI, fixes #74

• skip plane detection if fallback initiated prior to reconstruct
• implement timeout for plane detector
• implement detected planes limit for plane detector
• add respective configuration options lod11-fallback-time (in ms) and lod11-fallback-planes
• add rf_extrusion_mode attribute (values can be: standard, fallback, skip)
• rename rf_status to rf_success
• compute attributes with lod1.1 extrusion
  • volume
  • val3dity
  • rmse
• set some attributes to null when skipping or doing lod11 fallback
  • h_[min/max/90p]
  • n_planes
  • volume
  • val3dity
  • rmse
• set sensible default values for lod11 fallback time and planes