Flet-navigator

This release is last, it means that navigator is not supported anymore. But it doesn't makes it unusable. You can still push new issues and ask for help!

- **Now each `ROTATE` animation has random rotation angle target.**
- **New animations: `SHRINK_VERTICAL`, `CUSTOM`.**
- **Implemented feature to create custom animations.**
- **Optimized animations so they would not try to animate `AppBar` (its impossible).**
- **New global: `anon_argless`.**
- **Code cleanup/fixes/optimizations.**
- **Updated version (`FLET_NAVIGATOR_VERSION`).**
- **Updated documentation.**
- **Updated ReadMe.**
- **New release.**

Thank you for being with me!

- **New global functions: `render`, `anon`, `parameters`.**
- **New decorator: `global_template`.**
- **Templates extending: Global templates (+ `template` function update).**
- **New `PageData` methods: `PageData::navigate`, `PageData::navigate_homepage`.**
- **`virtual` property for both navigators.**
- **Code cleanup/fixes/optimizations.**
- **Updated version (`FLET_NAVIGATOR_VERSION`).**
- **Updated documentation.**
- **Updated ReadMe.**
- **New release.**

- **Implemented default 404 page.**
- **Now calling `route_changed_handler` before page load.**
- **Fixed `len` statement fail. (8).**
- **Updated parameters name checking.**
- **Updated documentation.**
- **Updated ReadMe.**
- **New version.**

- **Fixed boolean parsing in URL parameters.**
- **Added `parameters` argument in `FletNavigator::navigate`.**
- **Implement `__repr__` for `PageData`.**
- **New function `add` in `PageData`.**
- **New animation - `SHRINK`.**
- **Updated documentation.**
- **Updated ReadMe.**
- **New version.**

- **Implemented `route` decorator.**
- **Finished animations: improved fade animations, added more animations, more customizable.**
- **Updated documentation.**
- **Updated ReadMe.**
- **New version.**

- **Made `template` arguments optional.**
- **Implemented page ID's.**
- **Each appbar for each page. (Issue 4).**
- **Updated documentation.**
- **Updated ReadMe.**
- **New version.**