Implement forgot password fragment

[The Figma document](https://www.figma.com/file/uLiqrlxmOB5xCppIzmiUXV/Teacher-Workout?node-id=0%3A1) contains the entire UI of the project.

You can export any image (asset) directly from Figma. [Here's how](https://drive.google.com/file/d/1KJncuAGFvKEo6zrjC9H3O59auITE0q2h/view).

**Please do not try to recreate the UI design exactly.** Prioritize using de default UI mobile components, and following the material design guidelines. The UI objects should be positioned roughly the same as in the Figma screens.

[The mobile flow can be found in the project Wiki](https://github.com/code4romania/teacher-workout-backend/wiki/Teacher-Workout-Mobile-flow).

_Please define related colors and text & button styles in the corresponding values files. Please extract all text values in the corresponding xml files so we can easily adjust them. <3_

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