Merge common code

[panagiotisbellias]

After these are completed:

• [x] #23
• [x] #27
• [x] #85
• [ ] #96

consider these:

• [x] combine AdminSeeder class and RoleSeeder class to one
• [x] extract common code in GlobalExceptionHandler

Note: check before refactoring for the latest changes and future developments and review what and if it is still needed

[panagiotisbellias]

@jcilacad Review my suggestion please and assign this issue to me if you agree or close it as not planned in case there is no need for that

Thanks

[jcilacad]

@panagiotisbellias go for it.

[panagiotisbellias]

Done