Convert .tgs with go libraries (and cgo) (telegram) (#1569)

This commit adds support for go/cgo tgs conversion when building with the -tags `cgo`
The default binaries are still "pure" go and uses the old way of converting.

* Move lottie_convert.py conversion code to its own file

* Add optional libtgsconverter

* Update vendor

* Apply suggestions from code review

* Update bridge/helper/libtgsconverter.go

Co-authored-by: Wim <wim@42.be>

vendor/github.com/Benau/go_rlottie/lottie_lottiekeypath.cpp

@@ -0,0 +1,86 @@
+#include "lottie_lottiekeypath.h"
+
+#include <sstream>
+
+LOTKeyPath::LOTKeyPath(const std::string &keyPath)
+{
+    std::stringstream ss(keyPath);
+    std::string       item;
+
+    while (getline(ss, item, '.')) {
+        mKeys.push_back(item);
+    }
+}
+
+bool LOTKeyPath::matches(const std::string &key, uint depth)
+{
+    if (skip(key)) {
+        // This is an object we programatically create.
+        return true;
+    }
+    if (depth > size()) {
+        return false;
+    }
+    if ((mKeys[depth] == key) || (mKeys[depth] == "*") ||
+        (mKeys[depth] == "**")) {
+        return true;
+    }
+    return false;
+}
+
+uint LOTKeyPath::nextDepth(const std::string key, uint depth)
+{
+    if (skip(key)) {
+        // If it's a container then we added programatically and it isn't a part
+        // of the keypath.
+        return depth;
+    }
+    if (mKeys[depth] != "**") {
+        // If it's not a globstar then it is part of the keypath.
+        return depth + 1;
+    }
+    if (depth == size()) {
+        // The last key is a globstar.
+        return depth;
+    }
+    if (mKeys[depth + 1] == key) {
+        // We are a globstar and the next key is our current key so consume
+        // both.
+        return depth + 2;
+    }
+    return depth;
+}
+
+bool LOTKeyPath::fullyResolvesTo(const std::string key, uint depth)
+{
+    if (depth > mKeys.size()) {
+        return false;
+    }
+
+    bool isLastDepth = (depth == size());
+
+    if (!isGlobstar(depth)) {
+        bool matches = (mKeys[depth] == key) || isGlob(depth);
+        return (isLastDepth || (depth == size() - 1 && endsWithGlobstar())) &&
+               matches;
+    }
+
+    bool isGlobstarButNextKeyMatches = !isLastDepth && mKeys[depth + 1] == key;
+    if (isGlobstarButNextKeyMatches) {
+        return depth == size() - 1 ||
+               (depth == size() - 2 && endsWithGlobstar());
+    }
+
+    if (isLastDepth) {
+        return true;
+    }
+
+    if (depth + 1 < size()) {
+        // We are a globstar but there is more than 1 key after the globstar we
+        // we can't fully match.
+        return false;
+    }
+    // Return whether the next key (which we now know is the last one) is the
+    // same as the current key.
+    return mKeys[depth + 1] == key;
+}