[FEATURE] Add the Form Elements components

[albx]

Create a set of reusable Razor components for form elements, according to Bootstrap Italia - Form Elements. Components should include Input, Select, Checkbox, Radio, Switch, and support all documented variants and accessibility features.

Requirements:

• Implement Razor components (e.g., BitInput.razor, BitSelect.razor, BitCheckbox.razor, BitRadio.razor, BitSwitch.razor) for each form element, following Bootstrap Italia styles.
• Support all input types (text, password, email, etc.), select options, checkbox/radio groups, and switches.
• Expose parameters for label, value, validation, and ARIA/accessibility attributes.
• Ensure accessibility best practices are followed.
• Add XML documentation for all public parameters.

Acceptance Criteria:

• Components render valid Bootstrap Italia markup for each form element.
• All documented variants and features are supported via parameters.
• Components are unit tested for all major variants and use cases.
• Usage examples are provided in the documentation or a sample page.

References:

• Bootstrap Italia - Form Elements Documentation

[albx]

as the components related to form are many and this is the only feature I plan to add for the 0.2.0 version. I will create an issue for each component, keeping this issue as parent.