chore: expose manifest reading and jsonwall as packages

[letFunny]

• Have you signed the CLA?

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References:

• https://github.com/golang-standards/project-layout
• https://spdx.dev/learn/handling-license-info/

Relevant excerpts:

/pkg
Library code that's ok to use by external applications (e.g., /pkg/mypubliclib). Other projects will import these libraries > expecting them to work, so think twice before you put something here
link

[cjdcordeiro]

We'll likely need to add the new licensing headers to each one of these source files

[cjdcordeiro]

thanks for adding the licensing headers. they lgtm

[cjdcordeiro]

Note

pls ignore the failed RTD check. I've enabled the automatic generation of PR docs, which will start passing once #185 is merged

[cjdcordeiro]

Given that chisel/internal is under AGPL, is this ok?

[letFunny]

Honestly, I am not sure. I have to read more about licensing, but it looks like it will not be okay, we would have to extract the common components into a Apache-2.0 package that is imported by both the AGPL and this one, but I am not really sure.

[cjdcordeiro]

Same comment here as above

[letFunny]

I am blocking this until we solve all the questions regarding copyright and licensing.