[#896] More options for handling duplicate alias in morley-client

Description

Problem: Currently, morley-client fails with an exception when an alias for a contract being originated already exists and we're not willing to overwrite it. Occasionally we want other behaviours, e.g. not saving the alias at all, or keeping the old one.

Solution: replace odReplaceExisting boolean flag with a 4-way enum datatype AliasBehavior.

Related issue(s)

Resolves #896 (closed)

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