Check for valid list file names #675
Description
TM only works properly for list names that are alphanumeric, plus underscores, as documented in the manual. However the site update code processes such lists, leading to a situation where some functionality works for those users but most does not.
Related: TravelMapping/Web#805
What should be the severity of this error? Should offending list files be ignored and reported in the site update log? Should the existence of one or more cause a site update failure?
It's possible that the best solution lies within GitHub, so that only files with valid characters in their names (and we might also be able to enforce a length, which is documented to be limited to 48 characters and is a hard limit in the DB) get into the repository at all, greatly reducing the likelihood of an error occurring at site update time.