Explore implementing email notifications

[davidji99]

Sample:

csrf_token: <REDACTED>
tab: notifications
formname: add_rule
trigger_name: item_velocity
channel: email
action: item_velocity
config.team_ids: <INTEGER>
config.timeout: 1800
filter.0.path: level
filter.0.template: item_level
filter.0.op: gte
filter.0.val: 40
filter.1.window_size: 300
filter.1.window_count: 10
filter.1.template: item_velocity
filter.1.window_count: 10
filter.1.window_size: 300
filter.3.path: environment
filter.3.template: item_environment
filter.3.op: eq
filter.3.val: production
csrf_token: <REDACTED> (different value than above)