Implement bulk add of players from CSV

[JimThatcher]

Put code behind handleBulkAdd() method in PlayerListForm.tsx to open file select dialog to select a CSV file, then parse the CSV file and for each row in the file create a PlayerData object and call DbApi.createPlayerData() with each PlayerData.

[JimThatcher]

One option for addressing the player text data (in PlayerData) and the player image file might be to allow the file selection of the CSV file to be multi-select, to select the CSV file and all of the player image files from the same directory, then scan the list of selected files for the CSV, and while processing the CSV and calling createPlayerData for each line, also check the list of files for the image file for that player, and if it's there, upload it to /rest/db/player/[imageFileName.png]. This would address Issue #2 as well.