Add a possibility to use only tabs

[bobbybonifacia]

Currently there are two options for "Attribute indentation style": Mixed and Spaces. In case we would like to use only tabs, we have to set KeepFirstAttributeOnSameLine always to false. Pls add a possibility to use only tabs with KeepFirstAttributeOnSameLine set to true.

[grochocki]

With such a configuration, how would you expect attributes to be aligned?

[grochocki]

Adding Tabs as an option seems to make sense, but as you point out, it may lead to some interesting misalignment/conflict with KeepFirstAttributeOnSameLine. We should note this in the documentation, but otherwise not do anything to correct for this.