Add contact footer link and rename form

Author: DennisSimon

ts/components/footer.tsx

@@ -34,6 +34,7 @@ const linkRows: LinkRows[] = [
             { url: 'https://docs.0x.org/', text: 'Documentation', shouldOpenInNewTab: true },
             { url: constants.URL_GITHUB_ORG, text: 'GitHub', shouldOpenInNewTab: true },
             { url: 'https://docs.0x.org/protocol/docs', text: 'Protocol Spec', shouldOpenInNewTab: true },
+            { url: '/#contact', text: 'Contact Us' },
             {
                 url: 'https://ethereum.stackexchange.com/questions/tagged/0x',
                 text: 'Stack Exchange',

ts/components/modals/modal_contact.tsx

@@ -107,7 +107,7 @@ export class ModalContact extends React.Component<Props> {
                     <StyledDialogContent>
                         <Form onSubmit={this._onSubmitAsync.bind(this)} isSuccessful={isSuccessful}>
                             <Heading color={colors.textDarkPrimary} size={34} asElement="h2">
-                                Contact Sales
+                                Contact Us
                             </Heading>
                             {this._renderFormContent(errors)}
                             <ButtonRow>