Improve the certificate role extraction to get both PSP and PSD2 roles

[Akila94]

Description:
The certificate roles are defined in both non-eiDAS and eiDAS certs as as follows,

• PSP_AI
• PSP_PI
• PSP_AS
• PSP_IC

Hence the role validation should be done against the above role names, not according to the PSD2 role names such as AISP, PISP, etc.

But when it comes to the UK specification, their SSA body contains the PSD2 roles. We need to add a method to the CertificateContent class in order to extract the both PSP and PSD2 roles in this case.

Suggested Labels:
OB3, Accelerator