Improve the getting started page

[harry-xiao-xin]

Please give some environmental requirements for version 4.3.0, such as os information, gcc version, etc. When I install localstack on Ubuntu 20.04, following the get started page, however, it alerts "/lib/x86_64-linux-gnu/libm.so.6: version `GLIBC_2.35' not found (required by /tmp/_MEIvdsP9P/libpython3.11.so.1.0)". I hope a checklist for environmental information before getting started. Thank you.