This PR introduces an assertion during the component name refinement to
assert that the lookup syntax is well formed. If a developer
accidentally types ":" instead of "::" you will end up with a runtime
erorr that looks like:

```
Uncaught Error: Assertion Failed: fullName must be a proper full name
    at assert (vendor.js:52729)
    at Container.lookup (vendor.js:16581)
    at Class.lookup (vendor.js:43950)
    at layoutFor (vendor.js:28680)
    at lookupComponentPair (vendor.js:28697)
    at lookupComponent (vendor.js:28711)
    at RuntimeResolver._lookupComponentDefinition (vendor.js:28992)
    at RuntimeResolver.lookupComponentHandle (vendor.js:28837)
    at CompileTimeLookup.lookupComponentDefinition (vendor.js:25065)
    at LazyCompiler.resolveLayoutForTag (vendor.js:60366)
```

This message is not actionable for developers. This PR will causes a
compile time error to occur with the following information:

```
Malformed component lookup in "test.js". Got <Foo:Bar \/> but you must use \"::\" to indicate a lookup
```

Co-authored-by: Godfrey Chan <[email protected]>