reading Nuget pass, cleanup
added CredsMigration DU
saving migrated credentials
cleanup - extract GetAllPackageSources member
Cleanup - Moved ParseAuth member to PackageSources module
Cleanup - extract packagesource parsing to the dedicated module
save credentials on convert
do not overwrite password in config file
Introduced seperate NugetSourceAuthentication type
test for saving DepFile with EvnVar auth
Implement selective mode
removed askNumberedQuestion
cleanup - ApplyConfig funcion
some docs
Better docs for find-refs
Merge branch 'convert_from_nuget_support_credential_store' of github.com:theimowski/Paket

Conflicts:
	src/Paket.Core/Utils.fs
	src/Paket/Program.fs