Support a (now deprecated) single-argument use of addBowerPackageToProject

[mike-north]

A single-argument use of addBowerPackageToProject used to work, until #4430 . This is causing some problems ( Gaurav0/ember-cli-jquery-ui#14 )

For example

addBowerPackageToProject('jquery-ui#1.11.1');

This PR adds support for this use back in to ember-cli, and deprecates it since we eventually want to get everyone using the two-argument variant

addBowerPackageToProject('jquery-ui', '1.11.1');

[stavarotti]

Any reason why the following now raises a deprecation notice?

this.addBowerPackageToProject('typography', 'https://github.xyz.com/UX/typography.git#1.0.1', {
  saveDev: true
})

Deprecation notice:

DEPRECATION: passing https://github.xyz.com/UX/typography.git#1.0.1 directly to `addBowerPackageToProject` will soon be unsupported.
You may want to replace this with `addBowerPackageToProject('https://github.xyz.com/UX/typography.git', '1.0.1')`

We use private repos that are not published to npm and hence the need to specify both the source and target. If we change to the recommended way, per the deprecation notice, we get an installation error:

Installing browser packages via Bower...
  not-cached https://github.xyz.com/UX/typography.git=https://github.xyz.com/UX/typography.git#1.0.1
Failed to execute "git ls-remote --tags --heads https://github.xyz.com/UX/typography.git=https://github.xyz.com/UX/typography.git", exit code of #128
fatal: https://github.xyz.com/UX/typography.git=https://github.xyz.com/UX/typography.git/info/refs not valid: is this a git repository?

Error: Failed to execute "git ls-remote --tags --heads https://github.xyz.com/UX/typography.git=https://github.xyz.com/UX/typography.git", exit code of #128
fatal: https://github.xyz.com/UX/typography.git=https://github.xyz.com/UX/typography.git/info/refs not valid: is this a git repository?