fix: Added linux_run script for LD_LIBRARY_PATH.

[MGlolenstine]

In Linux, there's a problem when .so files (dynamic libraries) get copied into plugin/linux they're not found when running.

I've added a run script that changes the LD_LIBRARY_PATH, which is the path that Linux uses to search for dynamic libraries.

After the execution is completed, the environment variable is reset back to the previous value.

Usage:

Go into the root of your project and execute ./sh/linux_run, and it should execute the same way as it does on other platforms when you run flutter run -d <platform>.

Notes:

• I'm not sure this is the best approach, but it's the best I've managed to get working.

[thlorenz]

Awesome, this is great! All this will be replaced once we get a proper rid command line tool going, but for now this works.

Thanks!