Copy over config file to new location on windows

[rullzer]

Fixes #766

I didn't test yet as my windows VM does funny things. So a quick run appreciated @camilasan

[juliusknorr]

Code makes sense. 👍

[jpnurmi]

👍 looks good

The old config path with some additional entries for testing:

C:\>tree /F C:\Users\jpnurmi\AppData\Local\Nextcloud
Folder PATH listing for volume OS
Volume serial number is 000055F7 EC39:3404
C:\USERS\JPNURMI\APPDATA\LOCAL\NEXTCLOUD
│   cookies0.db
│   nextcloud.cfg
│
├───empty
└───subdir
    ├───subdir1
    │       file1.txt
    │
    └───subdir2
            file2.txt

Nuke the new config path:

C:\>rd /S /Q C:\Users\jpnurmi\AppData\Roaming\Nextcloud

C:\>tree /F C:\Users\jpnurmi\AppData\Roaming\Nextcloud
Folder PATH listing for volume OS
Volume serial number is 0000DD15 EC39:3404
C:\USERS\JPNURMI\APPDATA\ROAMING\NEXTCLOUD
Invalid path - \USERS\JPNURMI\APPDATA\ROAMING\NEXTCLOUD
No subfolders exist

After launching the client:

C:\>tree /F C:\Users\jpnurmi\AppData\Roaming\Nextcloud
Folder PATH listing for volume OS
Volume serial number is 0000B5E0 EC39:3404
C:\USERS\JPNURMI\APPDATA\ROAMING\NEXTCLOUD
│   cookies0.db
│   nextcloud.cfg
│
├───empty
└───subdir
    ├───subdir1
    │       file1.txt
    │
    └───subdir2
            file2.txt

[rullzer]

Thanks for testing @jpnurmi