Generate list of series logos based on file patterns

[Latent-Logic]

Add another web-accessible handler to give a list of all of the series logos that are found dynamically in the resources repository. This way new convention logos can be added dynamically as needed. This links with Latent-Logic/TSSSF-Frontend#7

[Latent-Logic]

Also probably need to update the card generation python to find and load the new png for the symbol