Add Additional PR Checks

[makermelissa]

Now that we are checking the features, some additional checks that would be nice for PRs to have are:

• A "date_added" field is present and has a valid value
• A "family" field is present and of a supported type
• Image sizes are appropriate
• The image in the board file is present
• If board is set to not display due to lack of info, then maybe skip some of these checks
• No contribute Section includes

That should cover the most common things I tend to see that I would request changes for or update at a later date once I notice the info is missing.

[makermelissa]

As noted in #962, a contribute section should not be part of the PR, so this is something else to check.

[makermelissa]

I just had another thought, but this is more of a bonus. Perhaps it can figure out what the bootloader_id is, check if the value is correct, and if not then inform the user.