Remove Docker files from repository (0.105.2)

[micahsnyder]

The supported Docker files used to build the official clamav images are now located here: https://github.com/Cisco-Talos/clamav-docker

Also fix some minor errors in the INSTALL.md file.

Cherry-pick of #764

[ragusaa]

Attempting to build the container from the instructions did not work for me. I got this error

/bin/sh: 1: curl: not found
-- The C compiler identification is GNU 10.2.1
-- The CXX compiler identification is GNU 10.2.1
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Found Git: /usr/bin/git (found version "2.30.2") 
-- Rust tool `cargo` not found.
-- Rust tool `rustc` not found.
-- Rust tool `rustup` not found.
-- Rust tool `rust-gdb` not found.
-- Rust tool `rust-lldb` not found.
-- Rust tool `rustdoc` not found.
-- Rust tool `rustfmt` not found.
-- Rust tool `bindgen` not found.
CMake Error at cmake/FindRust.cmake:289 (string):
  string sub-command STRIP requires two arguments.
Call Stack (most recent call first):
  CMakeLists.txt:124 (find_package)


CMake Error at /usr/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:165 (message):
  Could NOT find Rust (missing: cargo_EXECUTABLE)
Call Stack (most recent call first):
  /usr/share/cmake-3.18/Modules/FindPackageHandleStandardArgs.cmake:458 (_FPHSA_FAILURE_MESSAGE)
  cmake/FindRust.cmake:315 (find_package_handle_standard_args)
  CMakeLists.txt:124 (find_package)

[micahsnyder]

That error looks familiar to me as well, though I don't remember when I saw it or why.

[micahsnyder]

Note: the main PR is #764. This current one is a copy for the 0.105 release.

[ragusaa]

May be better to have this be a link to the actual repo, so that the user can copy/paste to check out the repo. I.e. https://github.com/Cisco-Talos/clamav-docker