Input bar delegation

[AntonPalich]

ChatInputBarDelegate has been used for internal purposes, but now it purpose is to notify external users about UI events (requested in #40). ChatInputBar notifies its presenter using direct method calls (classic MVP pattern) instead of using delegation pattern.

[AntonPalich]

@diegosanchezr Please, take a look

[codecov-io]

Current coverage is 62.03%

Merging #50 into dev will increase coverage by +0.06% as of 90d0f93

@@              dev     #50   diff @@
=====================================
  Files          57      57       
  Stmts        2819    2824     +5
  Branches        0       0       
  Methods         0       0       
=====================================
+ Hit          1747    1752     +5
  Partial         0       0       
  Missed       1072    1072       

Review entire Coverage Diff as of 90d0f93

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