Build an abstraction layer that lives behind a `pcs` global variable on mobile-html pages for clients to interact with. It should hide `pagelib` and any other implementation details from the clients.
**Versioning**
`pcs.v1.` etc.
**Endpoints**
Appearance:
`setup(theme, dimImages, textSizeAdjustmentPercentage, margins, areTablesCollapsed, callback)` - Initial setup endpoint that combines multiple calls that usually happen on initial article load
`setTheme(theme)` - set reading theme
`setDimImages(dimImages)` - set whether or not images are dimmed
`setMargins(margins)` - set margins
`setTextSizeAdjustment(adjustmentPercentage)` - set text size adjustment
`setAreTablesCollapsed(areTablesCollapsed)` - set whether or not tables are collapsed
Interactions:
`setInteractionHandler(interactionHandler)` T219998
Content:
`getSectionOffsets(...)` T219909
See child tickets for details. Naming should match conventions defined here instead of naming conventions proposed in the child tickets. eg `pcs.v1.setTheme` not `wmf.setTheme`