FB-339 New purchase process

[piotrpospiech]

• created trial page with license agreement
• added license agreement for paid plans (it is used in Stripe Payment Link)
• added Stripe Payment Links
• added email template
• fixed tsc config

[piotrpospiech]

@mkaliszewski

1. We can display message after completing checkout or redirect user. We decided to display a message.
2. We will configure forminer email later. We want to deploy it with this email for now.
3. Images will be displayed after deploy as they are static assets in the forminer website. The same is for the paid plan license which link is available in the Stripe checkout.