[WIP] Use trial period on regular plan instead of trial plan

[tdrivas]

trafficstars

Current Approach Currently, we create two separate subscriptions:

• A Trial Subscription (is_trial=True) that lasts for TRIAL_PERIOD_DAYS.
• A Paid Subscription that is created after the trial expires.

Problems with this approach:

• Handling multiple subscriptions for one user
• Extra logic to fetch, cancel or update trial and regular subscriptions separately.

New Approach

• User asks for a trial subscription
• if the user has no remaining organization trials, no subscription is created
• Otherwise, a subscription object is being created including, among others, a trial_plan, a regular plan and a default number of trial days.
• The trial subscription becomes active until the end of the trial.
• When the trial ends and depending on the user input (payment method), the subscription update its status (ACTIVE_ * / INACTIVE_ *)