Add API for working with rules (#2568)

* Add API for working with rules

* Add release note

* Change 'payees-get-rules' return type to RuleEntity[]

* Reuse existing handlers, make names not have 'payee', add two getters

* fix linter

* fix bad handler name

* fix broken handler name

* add test cases for 'getPayeeRules'

* fix broken test

* Remove unused locals

* Update packages/loot-core/src/types/api-handlers.d.ts

Co-authored-by: Matiss Janis Aboltins <matiss@mja.lv>

* Update packages/loot-core/src/types/server-handlers.d.ts

Co-authored-by: Matiss Janis Aboltins <matiss@mja.lv>

* Strict types and slightly improved return interface

* update test comment to match new API names

* fix linter issues

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Co-authored-by: Matiss Janis Aboltins <matiss@mja.lv>