Fix Civetweb Lua error reporting issue

[DL6ER]

What does this implement/fix?

This PR is largely analogous to civetweb/civetweb#1296. It adds the following extras specific to FTL:

• Increase LUA string buffer size from 60 to 256 characters. This is necessary as most standard Pi-hole scripts (in the already lengths path "/var/www/admin/scripts/pi-hole/") would otherwise exceed the buffer size and be printed in an abbreviated form in stack tracebacks.
• Load bundled scripts (to date, only inspect) in a better (more central) place where it is also imported for the web Lua environment.

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Related issue or feature (if applicable): Fixes the issue discussed in pi-hole/web#3143

Pull request in docs with documentation (if applicable): N/A

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2. I have commented my proposed changes within the code.
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4. It is compatible with the EUPL 1.2 license
5. I have squashed any insignificant commits. (git rebase)

Checklist:

• The code change is tested and works locally.
• I based my code and PRs against the repositories developmental branch.
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• I have read the above and my PR is ready for review.

[DL6ER]

PR merged as is on CivetWeb repo: civetweb/civetweb#1296