v1.12.0: fix aliased GraphQL operations (#246)

* fix idle pconn fatal error

* add index method remove node by name
add ast method replace root operation type definition
add ast method remove object type definition

* add normalization with retry to grapqhl datasource

* add code for extracting nested children and arguments (#95)

* move code for determine child nodes

* add function to find all field arguments

* add lookup functionality

* fix linter errors

* add recursion stop condition (#96)

* fix review comments

Co-authored-by: Sergey Petrunin <spetrunin@users.noreply.github.com>

* fix being unable to reuse arguments for rest

* refactor to planning behavior struct

* fix error when no planner is provided

* remove unused code

* enforce dot as first non-space character in templates (TT-1769) (#98)

* enforce dot as first non-space character in templates

* extend test cases

* change request.header to request.headers

* add a failing test for alias in schema

* add logic to allow DataSourcePlanners to rewrite downstream field aliases

Co-authored-by: Sergey Petrunin <neyasut@gmail.com>
Co-authored-by: Sergey Petrunin <spetrunin@users.noreply.github.com>
Co-authored-by: Patric Vormstein <pvormstein@googlemail.com>