Node: remove Florencenet, rename Florencenobanet into Florencenet

Context

Florencenet is no longer relevant since PsFLoren was chosen instead of PsFLorBA by the community. This patch removes the built-in network configuration for Florencenet. It also renames Florencenobanet into Florencenet.

The update to the changelog was done in !2702 (closed).

Manually testing the MR

./tezos-node config init --network florencenet
./tezos-node run

Then check that the network chain name is FLORENCENOBANET (not FLORENCENET).

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
• Select suitable reviewers using the Reviewers field below.