Rtfde

* Pin RTFDE to lark 1.1.8
* Exclude test modules from being installed as top level module when building the wheel from source.
* Remove unnecessary shebang from non-standalone code
* Updated all licenses to consistently state LGPLv3
* Updated python version to v3.8 and removed use of v3.9 byte-manipulation methods
- Next major change, when 3.9 is more commonly used, we will push up to 3.9 and revert it forward again.

The major change here is that I updated RTFDE to only work with bytes and leave all encoding up to the downstream library. Please update your code as necessary!

Updated to only work with bytes.
Added far greater unicode support.
Fixed various whitespace issues.
Added proper htmlrtf support.
Added support for extracting (but not parsing binary data).
Update grammar to be far more explicit when extracting objects.
Fixes to ensure deencapsulation handles whitespace properly.
Adds grammar composer to make grammar modifications more clearly defined.
Adding support for surrogates which use raw unicode instead of 16bit signed encoding.
Added better handling of parsing unicode HH replacement chars.