Check if Sherlock is package or script at runtime

[ppfeister]

Description

Many tutorials and walkthroughs exist for Sherlock, and they all use the old not-really-installed "install" method. With this, after the transition to a proper installable package, many users have opened bug reports relating to failed imports, when following these now outdated guides.

One of two things should happen to alleviate this --

• Choose at runtime between proper module imports and relative script imports
• Test at runtime if Sherlock is being ran as a package or as a script, and display a more informative error message if as a script

The former is more "friendly" in that it allows for old-style use, but the latter is more "proper" in my mind and more assertive in its use as a package. I lean towards the latter.

Code of Conduct

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