[Keymap] Layout for FC660C with additions for mouse keys and few other changes (#6139)

* new keymap for the hasu with media keys and mac layout

* switch escape and grave

* switch to the usual default

* with play and stop

* add reset on fn layer

* add mouse buttons, move reset, update copyright

keyboards/fc660c/keymaps/siroleo/README.md

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+# Sid's mods for the fc660c
+
+Emulates original keymap with modifications for:
+
+- Media keys
+- Grave key(s)
+- Reset on the function layer
+- Mouse keys ala Tada68