Currently:
* 48to49 upgrades the machine stacks from 4000016 to 50000**16**
* 49to50 upgrades the machine stacks from 4000016 to 50000**18**
As a result, the versionUpgrader in arachne skips the 48to49 because it sees that the 49to50 also increments the setting version.
This is now fixed by making sure that the 49to50 upgrades from **5**000016 to 5000018.
CURA-8468
Things to note:
* Since there is no VersionUpgrader from 4.8 to 4.9, this versionUpgrader attempts to upgrade
files made in 4.8. This means that it touches files with setting_version = 16.
* The upgrade of the setting_version to 18 is currently commented out because we are not entirely
sure that 18 will be the setting_version in 5.0.
* This versionUpgrader removes the following three settings that were removed in libArachne
* "Compensate Wall Overlaps"
* "Compensate Outer Wall Overlaps"
* "Compensate Inner Wall Overlaps"
* The VersionUpgrader also disabled Fuzzy Skin from any profiles that may have it enabled, as fuzzy
skin currently doesn't work in libArachne.
* The printer definitions have NOT been updated to the new setting_version to avoid having to deal
with an enormous merge conflict in case the setting_version of 5.0 is something other than 18.
* Since the VersionUpgrader does not alter the setting_version, it will run every time Cura starts.
In short, this versionUpgrader runs and removes the deleted settings but it does not really change
the setting_version of any files.
Contributes to CURA-7683 and CURA-7656
