Add a form to create a new feature-flag

[MehulKChaudhari]

Issue Description

Add a form to create a new feature-flag

1. The form should have a Name, Description Input field
2. The cancel and create button

Match the RDS design system and use color and fonts.

For rough reference

Api:

/feature-flags POST

Payload:
{
"Name": "pagination feature.",
"Description": "Pagination feature in members site ",
"UserId": "RDS userid"
}

[MehulKChaudhari]

If you need any clarifications or any help please reach out to @MehulKChaudhari on discord