Make API test_multiple_paths green again

Update OperatingSystem entity and map remote to local paths
Update str_type parameter in Role entity name field
Improve StringField to convert to a tuple if a string is given as
str_type
Improve skip_if_sam helper method to deal with entities modified by
functools.partial
Merge pull request #1483 from elyezer/fix-api-test-multiple-paths

Make API test_multiple_paths green again
(API) Port old tests for hosts

Significantly update the definition of class `Host`: modify fields and override
the `build` method to properly create dependent entities. Enable CRUD tests for
hosts in module `test_multiple_paths`. Drop old CRUD tests for hosts.

Slightly clean up module `test_host_v2`.

Fix #1446.