Force texting hours at the campaign level

[ben-pr-p]

This PR:

1. Forces texting hours to be set at the campaign level by requiring that campaign.override_texting_hours and campaign.texting_hours_enforced is true, but setting those values on the client to true, and removing the option to remove them. It also removes the database default of US/Eastern on the time zone and makes the time zone required in the yup client side schema.

To easily run this migration, do:

alter table campaign alter column timezone drop default;

2. Fixes a bug on Postgres introduced by the MySQL branch due to differences between MySQL and Postgres returning(*) on insert.

3. Introduces a slight optimization to send message by removing the join on organization, which is now possible because we're guaranteed that the campaign has texting hours enforced. Defaults are hardcoded to avoid modifying the rest of the sendMessage validation logic

[bchrobot]

Drop required() here to match model definition.

[ben-pr-p]

Ah!