Add dependencies for tools which were missing them

[EdwardLarson]

• I have reviewed the OFRAK contributor guide and attest that this pull request is in accordance with it.

One sentence summary of this PR (This should go in the CHANGELOG!)
Mark dependencies on libmagic and strings utility.

Link to Related Issue(s)
These are tools which OFRAK depends on. On some platforms, like Mac, they are not necessarily installed. They should have been explicitly marked as dependencies so the ofrak deps command can find and install them when necessary.

Please describe the changes in your request.

Anyone you think should look at this, specifically?

[whyitfor]

Looking good! See one comment about raising a ComponentMissingDependencyError.

[whyitfor]

@EdwardLarson, can you add a "fixed" changelog to OFRAK core for the Magic issue? Otherwise I think this looks good!