Fix coding standards and PHPMD

FILE: /project/app/modules/custom/i18n_sso/i18n_sso.install
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12 | VIOLATION | Avoid using undefined variables such as '$schema' which will lead to PHP notices.
62 | VIOLATION | Avoid using undefined variables such as '$schema' which will lead to PHP notices.

FILE: /project/app/modules/custom/i18n_sso/src/Controller/TokenController.php
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62 | VIOLATION | Missing class import via use statement (line '62', column '18').
79 | VIOLATION | Missing class import via use statement (line '79', column '20').
107 | VIOLATION | Avoid using undefined variables such as '$data' which will lead to PHP notices.
108 | VIOLATION | Avoid using undefined variables such as '$data' which will lead to PHP notices.
109 | VIOLATION | Avoid using undefined variables such as '$data' which will lead to PHP notices.

FILE: /project/app/modules/custom/i18n_sso/src/EventSubscriber/SsoAllowOrigin.php
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59 | VIOLATION | Avoid using undefined variables such as '$events' which will lead to PHP notices.
60 | VIOLATION | Avoid using undefined variables such as '$events' which will lead to PHP notices.

FILE: /project/app/modules/custom/i18n_sso/src/Service/Token.php
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51 | VIOLATION | getToken accesses the super-global variable $_SERVER.
74 | VIOLATION | createToken accesses the super-global variable $_SERVER.
74 | VIOLATION | createToken accesses the super-global variable $_SERVER.
100 | VIOLATION | getUserId accesses the super-global variable $_SERVER.
149 | VIOLATION | deleteExpiredTokens accesses the super-global variable $_SERVER.