This is a change to IAM export/import functionality. For LDAP enabled
setups, it performs additional validations:
- for policy mappings on LDAP users and groups, it ensures that the
corresponding user or group DN exists and if so uses a normalized form
of these DNs for storage
- for access keys (service accounts), it updates (i.e. validates
existence and normalizes) the internally stored parent user DN and group
DNs.
This allows for a migration path for setups in which LDAP mappings have
been stored in previous versions of the server, where the name of the
mapping file stored on drives is not in a normalized form.
An administrator needs to execute:
`mc admin iam export ALIAS`
followed by
`mc admin iam import ALIAS /path/to/export/file`
The validations are more strict and returns errors when multiple
mappings are found for the same user/group DN. This is to ensure the
mappings stored by the server are unambiguous and to reduce the
potential for confusion.
Bonus **bug fix**: IAM export of access keys (service accounts) did not
export key name, description and expiration. This is fixed in this
change too.
Use `ODirectPoolSmall` buffers for inline data in PutObject.
Add a separate call for inline data that will fetch a buffer for the inline data before unmarshal.
