Add deprecation for old usages of cachable and readOnly in CPs

* Passing opts.cacheable to the constructor of ComputedProperty is deprecated
* Passing opts.readOnly to the constructor of ComputedProperty is deprecated
* Invoking `cacheable` in a computed property is preprecated.
* Invoking `readOnly` with aany params in a computed property is deprecated.
* Make InjectedProperty inherit `readOnly` from CPs prototype
[BUGFIX beta] Only register core libraries once.

In Ember CLI (and in our own test suite) many Ember.Application
instances are created.  This prevents each test from triggering
a warning that the library has already been registered.
remove ember-data hooks for making things sync

When they should instead be scheduled within
the ember run loop

refs emberjs/data#2477
Merge pull request #9717 from rwjblue/prevent-zillions-of-warnings-in-tests

[BUGFIX beta] Only register core libraries once.
[DOC beta] An attempt at additional TextSupport documentation, per #5065
Extract `appendView`, `destroyView` for testing

Defining `appendView` and `destroyView` in multiple tests is verbose,
repetitious, and copy-paste-error prone.
Merge pull request #9489 from cibernox/deprecate_cacheable_method_in_cps

Add deprecation for old usages of cachable and readOnly in CPs
Merge pull request #9374 from tehcurtis/5065_better_document_component_actions

[DOC beta] First pass at additional TextSupport documentation, per #5065
Merge pull request #9769 from seanpdoyle/view-helpers-extraction

Extract `appendView`, `destroyView` for testing
Merge pull request #9764 from fivetanley/remove-ember-data-cruft

remove ember-data hooks for making things sync
Failing tests for href, class, booleans, value
Introduce AttrNode, new HTMLBars attribute syntax
Port attrs and classes via bind-attr to AttrNode
Add SVG attribute support
Support maxlength and nonmatching reflections
Add a feature flag for attribute syntax