Fmetools

* Relax FME version requirements from 0.7.0 release.

* Fix type annotations when using Python 3.8 and earlier.

* Add HTML docs and expanded existing docstrings.
* Clarify which components are considered part of the public API.
* Add type annotations.
* `fmetools.plugins.FMEEnhancedTransformer`: Support Bulk Mode by default.

* Rename `fmetools.plugins.FMETransformer` to `FMEBaseTransformer`
to avoid potential confusion with `fmeobjects.FMETransformer`.
Instantiating `fmetools.plugins.FMETransformer` now emits a warning,
and will be removed in a future release.
* `fmetools.paramparsing.TransformerParameterParser`: Support FME >= b23264.

* Add `fmetools.paramparsing.TransformerParameterParser`: a class for parsing
internal attribute values from transformer parameters. Requires FME 2023.
* Require Python 3.7+.

* Fixed error when parsing custom proxy URLs starting with 'http'