Drop support for 4.14 kernels

The 4.14 Linux kernel became end of life on 10 Jan 2024. Pixie has maintained support for kernels 4.14 and later since its initial creation. Deprecating older kernels allows us to take advantage of new eBPF features and also remove workarounds / tradeoffs required to support these older kernels.

This issue tracks the changes to remove 4.14 support and update our docs.