Use Z3-TurnKey instead of a bespoke Z3 build

[shonfeder]

Closes #213 (I hope!)

Our bespoke build and local installation of the Z3 API dependency adds a lot of configuration overhead and brittleness
to our build. While investigating #213, I read about Z3-Turnkey on https://stackoverflow.com/a/62015869/1187277. The purpose of this library is to provide a Java artifact that

1. ships its own native libraries,
2. can use them without administrative privileges, and
3. can be obtained using Maven.

I'm hopeful that it can simplify our build overall, and address #213.

[shonfeder]

I just finished a clean build on macOS with this branch using Zulu. Here's my configuration:

% mvn -v
Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /Users/sf/opt/apache-maven-3.6.3
Java version: 1.8.0_265, vendor: Azul Systems, Inc., runtime: /Users/sf/opt/zulu8.48.0.53-ca-jdk8.0.265-macosx_x64/zulu-8.jdk/Contents/Home/jre
Default locale: en_US, platform encoding: UTF-8
OS name: "mac os x", version: "10.15.6", arch: "x86_64", family: "mac"

@istoilkovska, at your convenience, perhaps you could try a clean build off this branch, and see if it works for you as well? I recommend checking out the repo afresh, since this PR changes the 3rdparty libs and the current build configuration doesn't clean up after itself there.

Regardless of whether this solves #213, since it reduces the initial build time considerably and simplifies our dependencies and build configuration, and seems to be passing all our tests, I think we'll probably want to keep Z3-TurnKey until #182 is closed as per Z3Prover/z3#182 (comment), by integrating it into Z3 itself.

[konnov]

Wow! This is just amazing. Building z3 has been painful for quite a long time.

[konnov]

@shonfeder I just have merged your PR, as @Kukovec needs it to fix his issue.

[romac]

Really cool stuff! I didn't know about z3-turnkey, sounds like it could be very useful for the Scala wrapper we've been developing and using for Stainless/Inox at @epfl-lara.

[konnov]

I hope that the maintainer of z3-turnkey will keep doing their great work!

[shonfeder]

The author is trying to integrate it it into z3, but said they'll continue maintaining in tandem with z3 releases in the meantime: Z3Prover/z3#182 (comment)