Implemented basic classes #7349

Job	Run time
Build LPython to WASM	5m 45s
Build Jupyter Kernel	3m 33s
LPython CI (3.10, ubuntu-latest)	8m 50s
Test CPython Interop (@pythoncall)	1m 47s
LPython CI (3.10, macos-latest)	8m 35s
Check Debug build	2m 31s
LPython CI (3.10, windows-2019)	14m 24s
Run Integration tests with Python 3.9	1m 48s
Check Release build	2m 23s
Run Integration tests with Python 3.10	1m 49s
Run SymPy tests	2m 20s
Run Integration tests with Python 3.11	1m 44s
Test PIP Installable Packages	1m 20s
Run Integration tests with Python 3.12	1m 51s
Upload Tarball	32s
	59m 12s

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