v0.2.2 - Split binary versions, add download step

What's Changed

• Adjust for separate binaries (devnet, mainnet) by @andreibancioiu in #5
• Download data if missing by @andreibancioiu in #6

• Adjust entrypoint to accommodate separate node binaries: devnet, mainnet.
• Receive and handle the environment variables PROGRAM (node or rosetta) and NETWORK (mainnet or devnet).
• Simplify conditions / if statements
• export LD_LIBRARY_PATH (instead of copying libwasmer into /lib)
• Download archives, if instructed to do so:
  • Exporting DOWNLOAD_REGULAR_ARCHIVE=yes or true will download a regular daily archive
  • Exporting DOWNLOAD_NON_PRUNED_EPOCHS=yes or true will download epochs with non-pruned state, as specified by EPOCH_FIRST, EPOCH_LAST.

Related to: multiversx/mx-chain-rosetta-docker#24

Full Changelog: v0.2.1...v0.2.2