feat(components): add numbox component

[desmondinho]

Description

Add the numbox, a component representing an input field for entering/editing numeric values, and the input field base component, to the component library.

Closes #49

What's been done?

Added the components mentioned above with the following abilities:

InputFieldBase: Represents a base component for form input field components

Basically, it is the Textbox that will now act as a base component for all input field components like textbox, numbox and etc.

The only 2 things I changed are:

1. The Type parameter is now present only in the textbox to avoid confusions
2. The InputType enum no longer contains number and all date-related types to avoid confusions

Numbox: A component representing an input field for entering/editing numeric values

Basically, a textbox without the input type control to avoid confusions that:

• Supports int, long, short, float, double, decimal

Checklist

• My code follows the project's coding style and guidelines.
• I have included inline docs for my changes, where applicable.
• I have added, updated or removed tests according to my changes.
• All tests are passing.
• There's an open issue for the PR that I am making.

Notes

Most of the textbox tests should be moved into the InputFieldBaseTests.
I am kind of lazy about inputs testing. It is just a big frustration for me. I will do them properly later.