Bigger home and scratch dir

[sverhoeven]

In the SRC VM the OS disk almost full need more room for users. Lets have a scratch and home as additional SRC storage items. The storage items should be made available inside VM as /home and /scratch.

Each storage item can only be mounted on a single VM, so each VM will need own storage items.

Each storage item is persistent so if reused in a new VM it will contain stuff from old usage. So we should have instructions that explains that home should be reused and scratch should be empty each time.

To keep scratch clean we could remove files older than 14 days.

To replace /home from root disk with a storage item, we will need to

1. copy /home mounted on root disk to temp home,
2. perform mount,
3. copy temp home to new home and
4. remove temp home

See #77

[sverhoeven]

Running wflow_Meuse_ERA5-calibrated parameter set twice fills up disk during update loop. Running wflow_Rhine_ERA5-calibrated" parameter, just once fills up disk during update loop at 2002-08-27