Make it possible to replace content items with an unknown ID using recipes

[Piedone]

Is your feature request related to a problem? Please describe.

Copied from Lombiq/Helpful-Libraries#199 by @sarahelsaig.

Currently it's not possible to overwrite a content item with a recipe if its ContentItemId is unknown - for example if it was created from a recipe using "ContentItemId": "[js: uuid()]". We should include some recipe mechanism to get around this.

E.g. TestAddingMenuItemToBlogMainMenuAsync() in Lombiq Base Theme would benefit from this.

Describe the solution you'd like

1. Add a IGlobalMethodProvider that let's you find the ContentItemId from alias, e.g.
   "ContentItemId": "[js: idFromAlias('main-menu')]".
2. Create a new recipe step that removes a content item by query.

I'm not sure if either of these is possible during setup, if the alias index may not be populated yet?

Describe alternatives you've considered

Implementing the same thing in a custom module.

[MikeAlhayek]

What about other scenarios like locating an item by a serial number or some other unique identifier? I have not gave this much of a thought, but what if we add a new LocatingAsync event on the content manager so that we can locate an item using other identifiers like alias, serial number, and anything else we have a handler for?

[Piedone]

We could generalize it to use IContentHandleManager.GetContentItemIdAsync() behind the scenes, so any content handle would work. Along the lines of:

"ContentItemId": "[js: idFromHandle('alias:main-menu')]"

I.e., exactly what the Menu TagHelper does too.

[sebastienros]

handle('alias:main-menu') (my preference)
find('alias:main-menu')
load('alias:main-menu')

[Piedone]

Or anothernameforthesamethingwouldnthurt('alias:main-menu') :D.