feat: add cJSON and SQLite amalgamation source files under deps/

Add the cJSON library (cJSON.c, cJSON.h) and SQLite amalgamation
(sqlite3.c, sqlite3.h, sqlite3ext.h, shell.c) as vendored dependencies
in the deps/ directory for use by the project build system.

test/jinja/raw.wren

@@ -0,0 +1,11 @@
+// retoor <retoor@molodetz.nl>
+
+import "jinja" for Environment, DictLoader
+
+var env = Environment.new(DictLoader.new({
+  "raw_var": "{\% raw \%}{{ not_parsed }}{\% endraw \%}",
+  "raw_block": "{\% raw \%}{\% if true \%}nope{\% endif \%}{\% endraw \%}"
+}))
+
+System.print(env.getTemplate("raw_var").render({})) // expect: {{ not_parsed }}
+System.print(env.getTemplate("raw_block").render({})) // expect: {% if true %}nope{% endif %}