Apply drupal 8 coding standards

Found there are still major Drupal standard issues with the 8.x-1.x version. The major issues are listed below.

FILE: /var/www/html/web/modules/custom/jw_player/src/Jw_playerListBuilder.php
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FOUND 1 ERROR AND 1 WARNING AFFECTING 2 LINES
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 11 | ERROR   | Class name must use UpperCamel naming without underscores
 33 | WARNING | Only string literals should be passed to t() where possible
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FILE: /var/www/html/web/modules/custom/jw_player/src/Entity/Jw_player.php
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FOUND 1 ERROR AFFECTING 1 LINE
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 45 | ERROR | Class name must use UpperCamel naming without underscores
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FILE: /var/www/html/web/modules/custom/jw_player/src/Plugin/Field/FieldFormatter/JwplayerFormatter.php
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FOUND 0 ERRORS AND 6 WARNINGS AFFECTING 6 LINES
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  78 | WARNING | \Drupal calls should be avoided in classes, use dependency injection instead
  80 | WARNING | \Drupal calls should be avoided in classes, use dependency injection instead
 161 | WARNING | \Drupal calls should be avoided in classes, use dependency injection instead
 166 | WARNING | ImageStyle::load calls should be avoided in classes, use dependency injection instead
 198 | WARNING | Unused variable $preview_items.
 199 | WARNING | ImageStyle::load calls should be avoided in classes, use dependency injection instead
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FILE: /var/www/html/web/modules/custom/jw_player/src/Element/JwPlayer.php
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FOUND 1 ERROR AFFECTING 1 LINE
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 19 | ERROR | Long array syntax must not be used in doc comment code annotations
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FILE: /var/www/html/web/modules/custom/jw_player/src/Jw_playerInterface.php
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FOUND 1 ERROR AFFECTING 1 LINE
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 10 | ERROR | Interface name must use UpperCamel naming without underscores
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