Restructure Entrypoint Packages

[kchason]

Allows the package to be properly imported by migrating the entrypoint logic into the module itself.

Notes:

• The _version.py needs to be executed in setup.py since the module isn't in the path of the setup.py. If the directory is just appended with sys.path.append('sqlite_dissect') it creates a circular dependency since the required packages for the module are not yet installed.
• Bumped the version number from 0.1.0 to 0.1.1
• Maintained main.py as a naive wrapper for sqlite_dissect.entrypoint:cli() for backwards compatibility and compliance with existing documentation. Documentation for import will be added in a subsequent PR to allow this to resolve the bug identified in v0.1.0

[kchason]

References #18

[dc3-tsd]

Reviewed by TD.