fix(datepicker): support [email protected]'s 'fullTemplateTypeCheck'

[amitport]

Bug description or feature request:

when trying to build with "fullTemplateTypeCheck": true:

node_modules\ngx-bootstrap\datepicker\daypicker.component.d.ts.DayPickerComponent.html(2,62): : Property 'uniqueId' is protected and only accessible within class 'DatePickerInnerComponent' and its subclasses.
node_modules\ngx-bootstrap\datepicker\daypicker.component.d.ts.DayPickerComponent.html(18,17): : Property 'uniqueId' is protected and only accessible within class 'DatePickerInnerComponent' and its subclasses.
node_modules\ngx-bootstrap\datepicker\daypicker.component.d.ts.DayPickerComponent.html(20,17): : Expected 1 arguments, but got 0.
node_modules\ngx-bootstrap\datepicker\monthpicker.component.d.ts.MonthPickerComponent.html(9,17): : Property 'uniqueId' is protected and only accessible within class 'DatePickerInnerComponent' and its subclasses.
node_modules\ngx-bootstrap\datepicker\monthpicker.component.d.ts.MonthPickerComponent.html(11,17): : Expected 1 arguments, but got 0.
node_modules\ngx-bootstrap\datepicker\yearpicker.component.d.ts.YearPickerComponent.html(10,17): : Property 'uniqueId' is protected and only accessible within class 'DatePickerInnerComponent' and its subclasses.
node_modules\ngx-bootstrap\datepicker\yearpicker.component.d.ts.YearPickerComponent.html(12,17): : Expected 1 arguments, but got 0.

Versions of ngx-bootstrap, Angular, and Bootstrap:

ngx-bootstrap: 2.0.0-rc.0
Angular: 5.2.0
Bootstrap: 4.0.0-beta.2

Build system: Angular CLI, System.js, webpack, starter seed:

Angular CLI

[valorkin]

nice! it's nice reason for small PR