[MultiDomainBundle] Added host aliases support

[yoshz]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Fixed tickets	none

Added the ability to configure aliases for each host.
With this configuration each host can have multiple domain names without adding a new host configuration for each domain.

[denbatte]

Hi @yoshz ,

Just a quick question: why would you define multiple aliases?
Could you explain your use case a bit more?

[yoshz]

If you have multiple domains for the same site you only have to add an alias and avoid an extra site in the admin selector.
Users don't understand why a website is in the selector twice but uses the same page tree.

I currently use this functionality to add a test domainname alias next to the live domainname to a existing site.

[yoshz]

I implemented a different way to solve our use case by overriding DomainConfiguration.
You still can merge this pull request if you think it usefull, otherwise you may close it.

[roderik]

@jockri this is the feature i was talking about :) I want this too :)

[jockri]

Looks like a good solution.
When you want different extra parameter values for each (aliased) domain, you can always define them separately.

[roderik]

@yoshz can you rebase your branch so i can merge this?