Retrieve file.platform object

Also moved platform test data from replicates to files, and updated AssayDetails to put divs around dt/dd, like everything else has now.
Display platforms from experiment.files
Merge remote-tracking branch 'origin/master' into 2469-platform-move
Correct display when no files for experiment

Was displaying platform line even if no files.
Merge remote-tracking branch 'origin/master' into 2469-platform-move
Update Jest test for moved platforms
Get library data from ALL replicates for exp

We used to only use the first replicate. This change gathers data from the libraries of all replicates for an experiment and presents them as comma separated in the Assay panel.
Revert to Assay info only from first replicate

This does NOT revert the code to the way it was. The rewrite to get information from *all* the libraries was much cleaner and simpler than it was, so I just removed the part about using all the replicates.
Merge remote-tracking branch 'origin/master' into 2469-platform-move
Merge remote-tracking branch 'origin/master' into 2469-platform-move
Use replicate.platform as backup

If an experiment’s files don’t have a platform, then look in the experiment’s first replicate and get the platform from there if it has one.
Merge remote-tracking branch 'origin/master' into 2469-platform-move
Merge remote-tracking branch 'origin/master' into 2469-platform-move
Merge remote-tracking branch 'origin/master' into 2469-platform-move
Merge pull request #533 from ENCODE-DCC/2469-platform-move

2469 Display platform from file obj; replicate obj as backup