envs/infinitime: remove environment

Remove the InfiniTime environment due to multiple issues:
- gcc-arm-embedded-10 was removed from nixpkgs
- adafruit-nrfutil depends on insecure python3.13-ecdsa-0.19.1 (CVE-2024-23342)

The environment is not functional and requires significant work to fix.

Author: Mic92

README.md

@@ -33,7 +33,6 @@ What environments should **not** include:
 | [Yocto](envs/yocto)                             | `yocto`               |
 | [Xilinx vitis](envs/xilinx-vitis)               | `xilinx-vitis`        |
 | [InfiniSim](envs/infinisim)                     | `infinisim`           |
-| [InfiniTime](envs/infinitime)                   | `infinitime`          |
 | [Ladybird](envs/ladybird)                       | `ladybird`            |
 | [buildroot](envs/buildroot)                     | `buildroot`           |
 | [zmk](envs/zmk)                                 | `zmk`                 |