[Chore] Replace firefly with scotty in tests

[int-index]

Problem: firefly depends on regex-pcre, which fails to build in certain configurations:

  regex-pcre > regex-pcre-0.95.0.0: library-dirs: /usr/lib is a relative path which makes no
  regex-pcre > sense (as there is nothing for it to be relative to). You can make paths
  regex-pcre > relative to the package database itself by using ${pkgroot}. (use --force to
  regex-pcre > override)
  regex-pcre > regex-pcre-0.95.0.0: dynamic-library-dirs: /usr/lib is a relative path which
  regex-pcre > makes no sense (as there is nothing for it to be relative to). You can make
  regex-pcre > paths relative to the package database itself by using ${pkgroot}. (use
  regex-pcre > --force to override)

The problem only occurs with stack on Windows. Therefore, there are two possible workarounds: (a) use cabal, (b) drop Windows support. However, we would like to support both build tools on all platforms if possible.

Solution: replace firefly with scotty, a different web server library that does not depend on regex-pcre.

[serokell-bot]

	1 Warning
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