Add method chaining for columns

[Tigrov]

Preparing to combine Column and ColumnSchema in one class

Related PR

• Add method chaining for columns db#852

Q	A
Is bugfix?	❌
New feature?	✔️/❌
Breaks BC?	❌
Fixed issues	yiisoft/db#854

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.27%. Comparing base (85c27c5) to head (32c617b).

❗ Current head 32c617b differs from pull request most recent head d1e7fe3

Please upload reports for the commit d1e7fe3 to get more accurate results.

Additional details and impacted files

@@            Coverage Diff            @@
##             master     #349   +/-   ##
=========================================
  Coverage     99.26%   99.27%           
  Complexity      282      282           
=========================================
  Files            23       23           
  Lines           821      824    +3     
=========================================
+ Hits            815      818    +3     
  Misses            6        6           

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[vjik]

Need to add info to changelog and upgrade