Add customization

[wzulfikar]

Add support for more customization:

• Use shorter name (data-feedbackfin-button to data-unfeed-button)
• Infer webhook endpoint from data-unfeed-button
• Infer name and email from data-unfeed-name and data-unfeed-email
• Allow customizing primary color via data-unfeed-primary-color (default color is #005dff)
• Allow including additional context (raw string) via data-unfeed-context
• Allow setting the form to open at start via data-unfeed-open
• Allow customizing footer text

Nit:

• Set focus to textarea after clicking the type (on changeType)

Preview (or see in jsbin):

<script src="https://unpkg.com/unfeed@^1" defer></script>

<button
    data-unfeed-button=""
    data-unfeed-name="John Doe"
    data-unfeed-email="john@example.com"
    data-unfeed-primary-color="#31ba64"
    data-unfeed-context="test at localhost"
    data-unfeed-footer="Hello world!"
    data-unfeed-open
>
    Send Feedback
  </button>