Handle ctrl+D

See merge request !3

Improve error message for command vmcreds2pdf

See merge request !2

- Added field validation to structures received from server API
- Completed vmattachsingle (but disabled - only present for testing the route)
- tpledit was removed by mistake in a previous commit: it's back now
- Bumped to version 1.9.3

Server:
- Changed max #cpus from 16 to 32
- Changed min ram from 256MB to 128MB
- Changed min VM name length from 4 to 1 char
- Bumped to version 1.9.3
- Completed /vms/{id}/attach route

nexush and nexus-cli: useradd, usersectcaps and vmaddaccess now display, in the usage help, the various potential capabilities that can be used.

Ongoing work on ticket #123: Update/cleanup code to only use shared structures for serialized objects

Added VM start time
Bumped server version to 1.9.2
Bumped client version to 1.9.2

Added src/client/cmdTemplate/templateListSingle.go which I had forgotten to add previously

Previously, the VM_LIST VM capability allowed one to list the VM as well as attach to it. This capability was too coarse. Instead, VM_LIST should only allow one to list the VM and nothing more. The VM_ATTACH capability was added specifically to allow a user to attach to the VM.

- added route to retrieve a single VM from its UUID
- added route to retrieve a single template from its UUID

client:
- added vmlistsingle to test above route (but then commented out)
- added tpllistsingle to test above route (but then commented out)

Bumped version to 1.8.10