Feat/add meta on build

[elizabethengelman]

What

Closes #1605

Why

Allows users to add additional meta to their contract wasm on build.

Known limitations

n/a

[leighmcculloch]

Looks good, three minor tweaks otherwise 👍🏻.

Have you tried deploying a contract built with the additional meta option?

[elizabethengelman]

Have you tried deploying a contract built with the additional meta option?

I have not yet, but will do that shortly! Great idea!

update:
just tested this on testnet, and verified that that meta included the new meta values added on build:

[leighmcculloch]

👏🏻

This could impact others, so we should do an announcement 📣 in Discord so folks know that it's appending a second custom section with the same name. @elizabethengelman can you do that?

[elizabethengelman]

This could impact others, so we should do an announcement 📣 in Discord so folks know that it's appending a second custom section with the same name. @elizabethengelman can you do that?

@leighmcculloch sure thing! does posting in #announcements make sense, or is there another channel?

[leighmcculloch]

#announcements make sense, or is there another channel?

It's a bit low level and won't be important for contract developers likely to know, so in the soroban-itself channel, starting a thread, and then we can mention folks we expect will be of interest. And anyone else can see thet hread and hopefully tag others if they know of anyone.