Request available slicers and slicing profiles from backend asynchronously when opening the slicing dialog
Request available slicers and slicing profiles from backend asynchronously when opening the slicing dialog

Should make sure that slicers and new profiles are detected correctly even without reload.

Could maybe help with #689

leductan-nguyen/RaionPi,spapadim/OctoPrint,jneves/OctoPrint,jneves/OctoPrint,shohei/Octoprint,shohei/Octoprint,mayoff/OctoPrint,Mikk36/OctoPrint,Javierma/OctoPrint-TFG,Salandora/OctoPrint,JackGavin13/octoprint-test-not-finished,leductan-nguyen/RaionPi,foosel/OctoPrint,beeverycreative/BEEweb,JackGavin13/octoprint-test-not-finished,CapnBry/OctoPrint,JackGavin13/octoprint-test-not-finished,foosel/OctoPrint,mrbeam/OctoPrint,Salandora/OctoPrint,masterhou/OctoPrint,uuv/OctoPrint,mayoff/OctoPrint,dansantee/OctoPrint,nicanor-romero/OctoPrint,ryanneufeld/OctoPrint,Skeen/OctoPrint,eliasbakken/OctoPrint,Javierma/OctoPrint-TFG,bicephale/OctoPrint,spapadim/OctoPrint,masterhou/OctoPrint,Salandora/OctoPrint,eliasbakken/OctoPrint,CapnBry/OctoPrint,punkkeks/OctoPrint,sstocker46/OctoPrint,mayoff/OctoPrint,leductan-nguyen/RaionPi,MaxOLydian/OctoPrint,shohei/Octoprint,ryanneufeld/OctoPrint,EZ3-India/EZ-Remote,MoonshineSG/OctoPrint,Javierma/OctoPrint-TFG,senttech/OctoPrint,EZ3-India/EZ-Remote,nickverschoor/OctoPrint,chriskoz/OctoPrint,dragondgold/OctoPrint,Salandora/OctoPrint,shaggythesheep/OctoPrint,eliasbakken/OctoPrint,nickverschoor/OctoPrint,MaxOLydian/OctoPrint,markwal/OctoPrint,JackGavin13/octoprint-test-not-finished,markwal/OctoPrint,punkkeks/OctoPrint,nicanor-romero/OctoPrint,chriskoz/OctoPrint,jneves/OctoPrint,Skeen/OctoPrint,senttech/OctoPrint,markwal/OctoPrint,javivi001/OctoPrint,senttech/OctoPrint,javivi001/OctoPrint,sstocker46/OctoPrint,MoonshineSG/OctoPrint,sstocker46/OctoPrint,beeverycreative/BEEweb,Jaesin/OctoPrint,Mikk36/OctoPrint,dragondgold/OctoPrint,SeveQ/OctoPrint,javivi001/OctoPrint,Javierma/OctoPrint-TFG,SeveQ/OctoPrint,bicephale/OctoPrint,spapadim/OctoPrint,CapnBry/OctoPrint,eddieparker/OctoPrint,mcanes/OctoPrint,ErikDeBruijn/OctoPrint,eddieparker/OctoPrint,SeveQ/OctoPrint,alex1818/OctoPrint,chriskoz/OctoPrint,beeverycreative/BEEweb,ErikDeBruijn/OctoPrint,Voxel8/OctoPrint,foosel/OctoPrint,dragondgold/OctoPrint,CapnBry/OctoPrint,MoonshineSG/OctoPrint,nicanor-romero/OctoPrint,EZ3-India/EZ-Remote,Mikk36/OctoPrint,ErikDeBruijn/OctoPrint,mrbeam/OctoPrint,uuv/OctoPrint,shaggythesheep/OctoPrint,EZ3-India/EZ-Remote,foosel/OctoPrint,alex1818/OctoPrint,mrbeam/OctoPrint,chriskoz/OctoPrint,senttech/OctoPrint,Skeen/OctoPrint,masterhou/OctoPrint,leductan-nguyen/RaionPi,beeverycreative/BEEweb,nickverschoor/OctoPrint,ryanneufeld/OctoPrint,dansantee/OctoPrint,shohei/Octoprint,bicephale/OctoPrint,Jaesin/OctoPrint,MoonshineSG/OctoPrint,punkkeks/OctoPrint,Jaesin/OctoPrint,mcanes/OctoPrint,nickverschoor/OctoPrint,mcanes/OctoPrint,eddieparker/OctoPrint,Jaesin/OctoPrint,dansantee/OctoPrint,Voxel8/OctoPrint,Voxel8/OctoPrint,alex1818/OctoPrint,MaxOLydian/OctoPrint,shohei/Octoprint,shaggythesheep/OctoPrint,bicephale/OctoPrint,ryanneufeld/OctoPrint,uuv/OctoPrint