[iguana] Fix several build issues

Summary:
This fixes a few build issues from iguana that have been caught by CI:

• Move the directory to src/ where it belongs, fixing the include paths and sanitizer linkage
• Fix the description because it's not bitcoin-tx
• Remove the redundant C++ parameters so it inherits from the high level project
• Exclude from the default install so we don't ship the binary that currently is an empty shell
• Work around a cmake/linker combo bug
• Build the iguana target first before running the tests on CI. This is not a behavior change because the dependencies are set properly, but it will help stop the build early if it fails so it makes parsing CI easier

Test Plan:

ninja all check-iguana install

Run the sanitizers build and the windows cross build.

Reviewers: #bitcoin_abc, tobias_ruck

Reviewed By: #bitcoin_abc, tobias_ruck

Differential Revision: https://reviews.bitcoinabc.org/D16811