Use common state for cloned view + Immutable set of paceholder salt + Improve fluent interface + Fix configs

[vjik]

Q	A
Is bugfix?	✔️
New feature?	✔️
Breaks BC?	✔️
Fixed issues	#188

• Use common state for cloned instances of View and WebView.

• Add method withClearedState() for View and WebView that cleared state of view (parameters, blocks, etc.).

• Replace mutable method setPlaceholderSalt() of ViewInterface to immutable withPlaceholderSalt().

• More methods of View and WebView returns self for improve fluent interface of classes.

• Fix configuration: set parameters after reset View and WebView.

• Improve changelog.

[samdark]

https://github.com/yiisoft/demo/pull/410

[samdark]

👍