Kintree

Updates
- Added support for InvenTree `ManufacturerPart` model introduced in https://github.com/inventree/InvenTree/pull/1417
- Decoupled manufacturer and supplier parts creation
- Updated InvenTree API package
- Added supplier's website link field in part form (fixes 34)
- Re-ordered manufacturer and supplier fields in part form


- Fixed Ferrite Bead template reference designator letter (`FB` instead of `L`)

Improved Settings
- General settings are now stored in `config/settings/general.yaml`
- InvenTree environment setting can now be loaded from this file and overwritten with environmental variable (if necessary)
- Internal Part Number settings from 26 are now stored in `config/settings/internal_part_number.yaml`
- Digi-Key search settings are now stored in `config/digikey/digikey_config.yaml`
- Added integration for settings requested by cdwilson in 29
- Updated settings to load from files instead of hard-coded

21
* Fix for listing "uncategorized" footprint folders, when KiCad footprint path was not set correctly
* Fix for preventing part creation to run if KiCad symbol/footprint window is closed: a previous action on that window would make it proceed
* Updated ferrite bead template: replace "supplier" fields with "manufacturer" fields
* Updated README

26
* User can make the unique ID length configurable via `settings.IPN_UNIQUE_ID_LENGTH`
* User can choose the variant suffix ID configurable via `settings.IPN_VARIANT_SUFFIX`
* The variant suffix is now optional via `settings.IPN_USE_VARIANT_SUFFIX`
* It adds the ability to use a "non-intelligent" IPN scheme with an optional fixed prefix via `settings.IPN_USE_FIXED_PREFIX`. If `IPN_USE_FIXED_PREFIX` == '' (default), no prefix is added to the IPN.

This update allows IPNs like the following:
* `000123`
* `123`
* `PREFIX-00123`
* `FOO-12345-A`
* `000123-01`

Updates
* Improved part creation result message handling
* Fields in part information form are now aligned (looks pretty now!)
* Updated InvenTree python API and fixed category parameters fetching
* Fix crash/bug related to KiCad template loading: it would error out if no template was associated to selected category
* Fix bug related to category selection: it wouldn't reload the full category list after clicking the "Confirm" button

Updates
* Updated categories and parameters lists
* Improved part creation flow for custom parts:
* More checks upfront to avoid loss of information after filling the part data form
* Local form checks for data integrity (check existence of part name and description)

KiCad
* KiCad symbol Value property is now replaced with IPN
GUI
* Implemented persistence of footprint (kicad_mod) selection
* Improved symbol template automatic selection