escalation policy: add user favorite support

[pnengchu]

• Identified the issue which this PR solves.
• Read the CONTRIBUTING document.
• Code builds clean without any errors or warnings.
• Added appropriate tests for any new functionality.
• All new and existing tests passed.
• Added comments in the code, where necessary.
• Ran make check to catch common errors. Fixed any that came up.

Description:
Users may now set favorites on Escalation Policies. This feature is replicated from Schedules and Services.

Which issue(s) this PR fixes:
Fixes #1085

Screenshots:

Additional Info:
High-Level overview of changes:

• A migration was added to include a new column, 'tgt_escalation_policy_id' for table 'user_favorites'
• The structs and schema for both Escalation Policy and Escalation Policy SearchOptions were updated with isFavorite/associated booleans for setting Favorites
• Relevant SQL queries have been updated to include escalation policies properties
• Front-end services were addressed to include UI changes when the onClick() is initiated by the end-user.
  -minor refactor of PolicyRouter.js

[dctalbot]

Suggested change

	isFavforite
	isFavorite

[pnengchu]

addressed. Good catch, thanks!

[mastercactapus]

Looks good, I found one bit that looks missed: when creating a new EP we should set it as a favorite of the current user. See graphql2/graphqlapp/service.go:149 as an example.

Short would be to add a favorite field to CreateEscalationPolicyInput and update the UI to pass it as true

[dctalbot]

We should write an integration test for this, but I'm OK doing that as a follow up PR. Looks great!

[dctalbot]

Not seeing the escalation policy favorited on creation - double check the input being passed into createPolicy

[mastercactapus]

We should add the integration test here, otherwise, there's a good chance the follow-up PR doesn't happen until something breaks.

There's already a favorites.ts file with all the other supported ones and a helper function to make it really easy. Let me know if you need help with this, you will just need to add a call to check similar to Schedules, but go to the /services page instead (service create has a SearchSelect for EP).

You will also need to make a small change in support/ep.ts to pass along the favorite parameter, and add the same to ep.d.ts in the types directory. (all under cypress/)

[mastercactapus]

Maybe we can use _.startCase so it says Set as Favorite Escalation Policy instead of Set as Favorite escalationpolicy

Suggested change

	? `Unset as a Favorite ${typeName.toLowerCase()}`
	: `Set as a Favorite ${typeName.toLowerCase()}`
	? `Unset as a Favorite ${_.startCase(typeName)}`
	: `Set as a Favorite ${_.startCase(typeName)}`

[pnengchu]

addressed, applied .toLowerCase() to account for Service, Rotation, Schedule checks

[mastercactapus]

Fall back to random:

Suggested change

	favorite: ep.favorite,
	favorite: ep.favorite ?? c.bool(),

[pnengchu]

addressed