Add Java requirement to install guide

[LeStarch]

Related Issue(s)
Has Unit Tests (y/n)
Documentation Included (y/n)

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Change Description

Fix install guide to include Java for non-x86_64/aarch64 systems.

[thomas-bc]

Any way we can format this to be less scary at first glance?
e.g.

6. For build host architectures other than x86_64 aarch64, Java is required to run the FPP tools

Or (better in my opinion) make it a note

Note: For build host architectures other than x86_64 aarch64, Java is required to run the FPP tools

Or anything really. Just trying not to make a 10second-read of this page mislead people in believing Java is a requirement for F´

[Joshua-Anderson]

Practically speaking, is anybody actually trying to build fprime on something other than x86_64/aarch64 systems?
Maybe an old 32-bit raspberry pi OS? Can't imagine too many people are using PPC or RISC.

I might just say that fprime only supports development on x86_64/aarch64 systems.

[thomas-bc]

@Joshua-Anderson yeah I agree with you, that's why I wouldn't really want to have a big bold "JAVA" requirement in the install guide.
But we did have one customer that was trying to build on something else, and not having Java installed caused an issue which wasn't as quickly identifiable as it should have been (corrected in #2620). Since we do have a better error handling now, I'm hesitant to add it as an entry in the system requirements as well.

[LeStarch]

Java is required for RISC-V. The current recommendations for cross-compiling RISC-V is to compile in an emulated RISC-V machine. I like @thomas-bc's suggestion of a note. I will make that change.