Allow to use system provided envoy

[chenrui333]

Describe the bug
Right now, func-e only install and run the specified envoy by itself, which caused some issue as

==> /opt/homebrew/Cellar/func-e/1.1.4/bin/func-e run --version
dyld: Symbol not found: __ZNKSt3__115basic_stringbufIcNS_11char_traitsIcEENS_9allocatorIcEEE3strEv
  Referenced from: /private/tmp/func-e-test-20230105-69203-1bzeb1u/.func-e/versions/1.24.1/bin/envoy (which was built for Mac OS X 13.0)
  Expected in: /usr/lib/libc++.1.dylib

To Reproduce
on macos-11, run func-e run

version: func-e 1.14
os: macOS 11
envoy: 1.24.1

Expected behavior
It should runs out fine.

Additional context
relates to Homebrew/homebrew-core#119899

[codefromthecrypt]

func-e's CLI was made to pass arguments literally to envoy, so not sure what value there is making a feature for this. e.g. func-e run xxxx calls envoy xxxx.

func-e can only support versions of envoy that the archive uses, and it recently dropped support for MacOS 11 tetratelabs/archive-envoy#42

[chenrui333]

Closing as we dropped macos-11 support. Thanks @codefromthecrypt!