[Feature] Ensure all packages have a manifest and a manifest-checker

[alessandrofelder]

Today's inspection suggests that the test_and_deploy workflow does not have a manifest checker in the following repos:

• bg-atlasapi Add check manifest to CI brainglobe-atlasapi#196
• bg-atlasgen Add manifest to ci bg-atlasgen#118
• brainglobe-segmentation Bring in line with other package CIs brainglobe-segmentation#167
• brainglobe-utils Add manifest to ci brainglobe-utils#32
• brainrender Add check manifest to ci brainrender#329
• imio Add manifest imio#54

[willGraham01]

@alessandrofelder these should all have the linked PRs staged and ready for review. To save spamming your inbox with 5+ PR reviews, I've just tagged you here 😅