code-ignore list not saved - no warning

[GitMensch]

• the UI allows the user to add huge amount of entries
• if there are "too much", then the list is not saved, while the user still gets the response " Changes saved. The list of ignored files will be updated during the next Open Hub analysis."

Things that should be fixed:

• return an error up to the UI if there was a problem with the save
• add length attributes to the ignore UI matching the rough size of elements that can be saved
• if possible: increase the size
• allow Allow: entries (or regex, but that's more compute intensive) as those are parsed easily (internally make two list: first match a file path in the Allow list, if in then skip the Disallow check; otherwise go over the Disallow list: if in then ignore the file, if not: keep it)

[a follow-up FR would be a button "validate now which checks the input for validity; this could also be implemented via javascript]