refactor(server/v2): simplify app manager (partial backport #22300)

[mergify]

Description

Simplify runtime/v2 and appmanager by removing builder for consistency.

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I have...

• included the correct type prefix in the PR title, you can find examples of the prefixes below:

• confirmed ! in the type prefix if API or client breaking change

• targeted the correct branch (see PR Targeting)

• provided a link to the relevant issue or specification

• reviewed "Files changed" and left comments if necessary

• included the necessary unit and integration tests

• added a changelog entry to CHANGELOG.md

• updated the relevant documentation or specification, including comments for documenting Go code

• confirmed all CI checks have passed

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I have...

• confirmed the correct type prefix in the PR title
• confirmed all author checklist items have been addressed
• reviewed state machine logic, API design and naming, documentation is accurate, tests and test coverage

Summary by CodeRabbit

• New Features

  • Introduced new methods for initializing and exporting application state.
  • Enhanced AppManager with new operational capabilities.
  • Added methods for closing the application and managing genesis state.

• Bug Fixes

  • Improved error handling in query handler registration.

• Documentation

  • Updated comments for clarity throughout the codebase.

• Refactor

  • Renamed methods for consistency and clarity, removing unnecessary prefixes.
  • Streamlined method calls and variable access in various components.
  • Restructured Build method for simplified app manager creation.

• Chores

  • Removed deprecated methods and fields to enhance code cleanliness.

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This is an automatic backport of pull request #22300 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 681366e has failed:

On branch mergify/bp/release/v0.52.x/pr-22300
Your branch is up to date with 'origin/release/v0.52.x'.

You are currently cherry-picking commit 681366e34.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   server/v2/cometbft/abci.go
	modified:   server/v2/cometbft/abci_test.go
	modified:   simapp/v2/app_di.go
	modified:   simapp/v2/app_test.go
	modified:   simapp/v2/export.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   runtime/v2/app.go
	deleted by us:   runtime/v2/builder.go
	deleted by us:   runtime/v2/manager.go
	deleted by us:   runtime/v2/module.go
	deleted by us:   server/v2/api/grpc/server.go
	deleted by us:   server/v2/api/rest/handler.go
	deleted by us:   server/v2/api/rest/server.go
	deleted by us:   server/v2/appmanager/appmanager.go
	deleted by us:   server/v2/appmanager/config.go
	deleted by us:   server/v2/appmanager/genesis.go
	deleted by us:   server/v2/appmanager/stf.go
	both modified:   server/v2/cometbft/server.go
	deleted by us:   server/v2/server_test.go
	deleted by us:   server/v2/stf/stf.go
	deleted by us:   server/v2/store/server.go
	deleted by us:   server/v2/types.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally