Link to connector docs/how-tos from the Downloads page

[patiencedaur]

Epic: Restructure Tarantool docs, stage 3
SME: @ LastoCHka42, @ NickVolynkin

Related to the https://github.com/tarantool/tarantool.io/ repository

Do this after #2667
Do it together with DevX

Details

In the Download section, find the connectors that are mentioned in the connectors doc. Provide links from the Download page to the corresponding docs.
Also consider providing links to tutorials for Python, Go, PHP, and C++ connectors )https://www.tarantool.io/en/doc/latest/how-to/getting_started_connectors/)