* PW-349: Show message if not on latest version of the extension

* PW-349: Replaced with correct \Exception type

* PW-349: Changed wording to "extension", added "Adyen" in the di name.

* PW-349: Added Session to store the github info and call github only once, changed severity of the message to MAJOR(warning) since the messages are only displayed with CRITICAL(1) or MAJOR(2), the inbox message is still stored with severity NOTICE(4), added quotes to href.

* PW-349: Removed try/catch in getText, renamed session variable