In order to prevent potential cross imports, container ID should be defined
in a separate package as a base type. A similar approach was used in the
NeoFS API design.
Create `pkg/container/id` package and replace container ID implementation to
it. Related API in `container` package is deprecated from now.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Remove nil if-statement from IDFromV2 function to which avoids checking the
correctness of the identifier format. From now IDFromV2 returns format error
on nil argument.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
