EIP-5 support in appkit

[Luivatra]

As described in https://github.com/ergoplatform/eips/blob/master/eip-0005.md

It would help remove ergoscript dependency for contracts that have constants that are not known beforehand. Currently either ergoscript needs to be compiled on the fly resulting in the risk that a change in compiler will give different ergotree, or the ergotree needs to be manipulated to replace the constant which especially in larger contracts with many constants can become messy.

So ideally appkit should support:

• Compiling ergoscript into eip-5 json
• Read eip-5 json and produce ergotree based on template bytes and supplied parameters