Instance backup name

[krystian-panek-tccc]

it would be nice to have some classifier/name or something passed to propose backup file name that will be respected when specifiied; just timestamp is not enough to know what state we are backing up

--name 'clean-with-prereqs' for example

https://github.com/wttech/aemc/blob/main/cmd/aem/instance_backup.go

[krystian-panek-vmltech]

slug spaces; e.g for aem 6.6 there is space before LTS