CLOUDSTACK-7871: allow VM and template details update using update APIs

Allows updating details (key/value) pair which updatse entries
invm_template_details and user_vm_details tables using updateVM and updateTemplate
APIs. This allows sys admins to update nics, controllers etc without DB hacking.

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
(cherry picked from commit 97fa4a023e2346b3b9f56bf213ed4125c371ca6d)
Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>