Add filters for custom data

[groenroos]

• Add WordPress filters raygun_custom_data and raygun_js_custom_data for optionally populating the user custom data of both PHP and JS errors
• Resolves Hook to attach custom data #44

[QuantumNightmare]

Thanks for submitting this PR. I'm not too familiar with wordpress development, and so have utilized AI to help with the review. A colleague who's more familiar than I may also chime in if they spot anything else.
It would be great if you could also add a section to the readme about how to use this feature - pointing out that the custom data is expected to be a string -> object mapping.
To aid with testing, please try out these changes (if you haven't already) and let me know the name of your Raygun plan or/and application where you send this data so I can verify things are coming through correctly - or just post some screen shots of test data. It would be good to test passing an invalid value to custom data, and a simple string -> object mapping, and also custom data where the object is not just a primitive object, e.g. an object with properties or an array.

[TheRealAgentK]

Added some feedback to the raised items, otherwise it's a good change imho.

It'd be great if after making adjustments, this could be tested and validated with screenshots (or an off-PR conversation with @QuantumNightmare as he suggested to look into your RG data).

[sumitramanga]

@robbieaverill Not sure if you have knowledge in Wordpress - Is it possible to have a peek of this PR if you do please? Just when you have some time :)

[robbieaverill]

Hi @sumitramanga, no, I don't have any WP experience, sorry.

[sumitramanga]

@robbieaverill No worries, thank you for replying!!

[sumitramanga]

Hi @groenroos ! Just wanted to check in and see if you can please apply the changes in order for us to move forward with this PR :) Looking forward to hearing from you!

[groenroos]

Hi @sumitramanga - apologies for the delay! I've now addressed the review comments, and added a section to the readme for documentation as requested.

We're still in the process of integrating this plugin to our current setup on our side, so we're not yet in a place to do any comprehensive testing in our real environment. Let me know if this isn't something you can test on your end, and I can add it to our roadmap!

[TheRealAgentK]

Hi @sumitramanga - apologies for the delay! I've now addressed the review comments, and added a section to the readme for documentation as requested.

We're still in the process of integrating this plugin to our current setup on our side, so we're not yet in a place to do any comprehensive testing in our real environment. Let me know if this isn't something you can test on your end, and I can add it to our roadmap!

Thanks @groenroos - I've resolved the two comments because I think they've been addressed well.

We'll have a chat internally if and how we can go about testing.