Allow `:` in ObjectIds

[ecordell]

The current regex:

^(([a-zA-Z0-9/_|\\-=+]{1,})|\\*)$

Doesn't allow for object ids that include : as separators, which are sometimes used in user identifiers.

[josephschorr]

In order to do so, we'd have to change the text format parser to treat any : after the first in the text format as part of the object ID space