Send email on new Plan Status

[GalGend]

Now that we have status updates for all plans, we'd like to inform our users of that.

We'd like to send an email to users in the following case:

• A new major Meirim status is given
• User follows that plan

The list of Meirim status is in status table. The list of plan follows is in plan_person.

We should use the existing email template, with the following content

״הפקדה להתנגדויות ברעננה - מוצקין 28 רעננה״, ״תוכנית הופקדה להתנגדויות ברעננה״ֿ

Same for cancelled/ approved.

[yaelal]

@GalGend can you help? branch issue_637 i have an issue with the email sending im getting an error: self signed certificate in certificate chain

[yaelal]

pr https://github.com/meirim-org/meirim/pull/644