fix(weavedrive): store headers as utf8 encoded

[jfrain99]

Weavedrive pulling data with Chinese characters is was resulting in special characters:

Desired: 
... { name: 'Description', value: 'Smartweave是不是要转到AO了？本文档介绍原子资产SmartWeave合约的标准接口。原子资产是SmartWeave合约及其在发布到Arweave的同一事务中初始化的数据。SmartWeave合约和数据共享一个交易ID。' } ...
Actual:
... {"name":"Description","value":"Smartweave/�-��pnSmartWeav��pnq�*�ID"} ...

If tried to decode using JSON.decode, get the following error:

[string ".handlers"]:559: [string "json"]:261: control character in string at line 1 col 2531

The issue is in the encoding: When saving to the emscripten file system, the files are not automatically encoded as utf-8 (the preferred encoding for Chinese characters). Now, we will encode the data manually.

[twilson63]

LGTM