Add missing B&R features

[yadvr]

Add the following missing UI features wrt B&R:

• Add offering support that imports external offering
• Support for backup user-defined schedule
• Restore volume and attach it to a VM from a backup

Screenshots:

[yadvr]

@utchoang cc @svenvogel since you'd done the snapshot schedule feature, can you pick this up - see http://primate-qa.cloudstack.cloud:8080/client/ for example of a backup schedule on the 'AdminFirstVM' VM. If possible can you prioritise this over your NSP support work? Thanks.

[utchoang]

Hi @rhtyd , I can't connect to http://primate-qa.cloudstack.cloud:8080/client/ because when login I have gotten the error message (image)
Although I have an input username / password correct.

[yadvr]

Hi @utchoang can you try again, there was an issue at mysql/mgmt server that has been temporarily fixed.

[yadvr]

Tested, LGTM.