Unify the $page property and add a fluent metadata helper

[caendesilva]

Breaking changes

The $post property has been renamed to $page to unify Blade layouts. The actual contents of the property is the same, however any published views must be changed. Since the meta.blade.php view and the config/hyde.php have both been changed they too need to be republished.

Metadata helper

Intended to be used in configs, the Meta helper gives an easy programmatic way to render HTML metadata.

Plan is to merge this with blog post data. As it is now it does not take care of removing duplicates in blog posts.

Usage:

Meta::name('foo', 'bar'),
Meta::property('foo', 'bar'),

Generates:

<meta name="foo" content="bar">
<meta property="og:foo" content="bar">

These are then now used in the Hyde configuration.

Fixes

Fix #382
Fix #375