Update screenshots in AtoM docs to show the BS5 variants instead of BS2

[anvit]

Update all screenshots that show BS2 elements with the BS5 version

List of screenshots sections:

User Manual

• [ ] Access content
• [ ] Add/Edit content
• [ ] Administer
• [ ] Data Templates
• [x] Getting Started
• [ ] Import/export
• [ ] Reports printing
• [ ] Translate

Developer Manual

• [ ] API

Admin Manual

• [ ] Customization
• [ ] Maintenance

[melaniekung]

Getting Started TODO:

• CAS login
• Custom homepage - do we need permission from a client? which client?