Feature/#328 Updates form-states.ts and form element components

[BeneRichi]

Pull request

This PR brings a couple of adjustments:

1. Removed the 'disabled' state from form-states.ts.
2. Added the native form element 'disabled' attribute to test the 'disabled' state on various components like e-input.vue, e-select.vue, and more.
3. Added form fields with 'disabled' attribute to r-forms.vue.

In addition: I improved the form fields (e-select, e-input, e-radio, e-checkbox, e-textarea) with a disabled state to have a consistent look. I aligned colors across all form elements with disabled state, added a light gray color to the label text, and added a "not-allowed" cursor pointer on hover.

These adjustments create a more unified and user-friendly interface.

Ticket

#328

Browser testing

• http://localhost:5173/styleguide/sandbox/forms

Checklist

• [x] I merged the current development branch (before testing)
• [x] Added JSDoc and styleguide demo
• [x] Tested all links in project relevant browsers
• [x] Tested all links in different screen sizes
• [ ] Did run automated tests and linters
• [ ] Did assign ticket
• [x] Double checked target branch

Review/Test checklist

• [x] Did review code and documentation
• [x] Tested all links in project relevant browsers
• [x] Tested all links in different screen sizes
• [x] Did check accessibility (Wave, only errors)
• [ ] Re-assign ticket to developer