feat: time based automation (#15022)

## Description

Add automations that trigger based on how long a conversation has been
in a given state.

## Type of change

- [ ] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?

- UI flows 
- Specs (https://github.com/chatwoot/chatwoot/pull/15021) 

## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Sony Mathew <sony@chatwoot.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>

config/features.yml

@@ -268,3 +268,7 @@
   display_name: WhatsApp Embedded Signup Flow
   enabled: false
   column: feature_flags_ext_1
+- name: delayed_automations
+  display_name: Delayed Automations
+  enabled: false
+  column: feature_flags_ext_1