fingerprints - descriptor Space removal, case normalization

cached-descriptors... fingerprint 50E9 30FB 6141 E9A7 DAD4 968E 58DE AA1B 06CF 4908 Remove the spaces from the fingerprints.

This isn't OpenPGP, no one goes around reading them off to people. You have to click-hold-carefully-drag to select the whole FP instead of a simple double-click. You have to postprocess strip them to make any use of them anywhere, including everywhere else in Tor... torctl, configs, etc. Nowhere else does Tor present/accept any fingerprints with spaces. And they currently waste about 60kB per descriptor set X all the nodes X frequency. The spaces have no substantive use whatsoever and are very annoying! Please remove them.

With that, normalize all displayed/coded fingerprints everywhere in Tor to be either upper or lower case... regardless of whether either/mixed case are supported/enforced as input. Lower case is suggested for better readability (ie: A4B8D0 vs. a4b8d0) and commonality with outputs of various hash programs.