Merge branch 'feat/jwt-token-system' into 'master'

src/main/java/no/ntnu/idi/stud/savingsapp/model/Role.java

src/main/java/no/ntnu/idi/stud/savingsapp/model/User.java

.../ntnu/idi/stud/savingsapp/properties/TokenProperties.java

...va/no/ntnu/idi/stud/savingsapp/security/AuthIdentity.java

...tnu/idi/stud/savingsapp/security/AuthorizationFilter.java

.../no/ntnu/idi/stud/savingsapp/security/SecurityConfig.java

...in/java/no/ntnu/idi/stud/savingsapp/utils/TokenUtils.java