Fix all broken links and old refs

[BrunoLad]

This PR addresses issue #309.
I tried to address all of them, hope I didn't miss any. A couple of comments below regarding some references and links that I wasn't able to update due to not having access or other reason and rationale behind some changes:

• Wasn't able to build the page and preview it live, so if you can validate that or give a brief explanation on how I can check that out, I can validate if everything is ok. I've just been validating the individual markdowns
• Noticed broken links to Ultimate RxJs course, maybe some issue with the drive file sharing (https://drive.google.com/uc?export=view&id=1qq2-q-eVe-F_-d0eSvTyqaGRjpfLDdJz 'Ultimate RxJS')?
• CombineAll seems to be deprecated and replaced with CombineLatestAll, so might want to rename section and update it
• Not sure if the CombineLatest example 3 link is working. Same thing for forkJoin: error correctly on the inner observable and catch the error on the outside. Could you test this out? Might be an interesting idea to link directly to the stackblitz link.
• Build your own combineLatest operator 🎥 - Kwinten Pisman. The original strongbrew.io blog is dead. Wayback machine wasn't able to preserve the video nicely like for indepth https://web.archive.org/web/20220814105219/https://blog.strongbrew.io/build-the-operators-from-rxjs-from-scratch/?lectureId=interval#app. and I guess the only viable resource are the source codes from the course, but not the videos. What I did was add a ref to combineLatest source code https://github.com/KwintenP/rxjs-operators-from-scratch/blob/master/src/observable/combineLatest.ts and remove the video icon and added a folder one.
  • Did the same thing for all the other references to blog.strongbrew.io
• There seems to be some missing commas (after provider and 2nd makeRequest) while opening plunker for example 6 of forkJoin. Also wasn't able to see the preview, don't know if it's just for me.
• I believe the pairwise jsbin example is referencing wrong lib: http://jsbin.com/keteyahido/1/edit?js,console
• Create seams deprecated Deprecate create static methods ReactiveX/rxjs#3982, might be worth to update this section, at a minimum to add a deprecation reference and what version it became deprecated.
• I took the liberty of updating the throw page and changing everything to throwError, let me know if this is OK. I updated the example of Throwing after 3 retries to specific example in retryWhen, but don't know if this is working properly (same issue I mentioned above with relative linking to certain headers), can you check?
• The first example of distinctUntilKeyChanged (Example 1: Compare based on key) Stackblitz (https://stackblitz.com/edit/typescript-hzta27?devtoolsheight=100&file=index.ts) is referencing to distinctUntilChanged example.
• The first example Stackblitz (https://stackblitz.com/edit/typescript-jpjcpg?file=index.ts&devtoolsheight=100) of ignoreElements example 1 (Example 1: Ignora all elements from source) is referencing an example from the retry operator.
• skip Example 2: Short hand for a specific filter use case jsBin and jsFiddle examples seems to not be building properly. Possibly a bad lib reference.
• bufferTime Example 1: Buffer for 2 seconds jsBin and jsFiddle seems to be broken. Typo in source variable, which is stopping it from running.
• timeout Example 1: Timeout after 2.5 seconds jsBin and jsFiddle aren't building properly

[btroncone]

@BrunoLad First off, I want to apologize for missing this. Life happened, this slipped my mind, and I just wasn't giving this project the attention it deserved for a period of time.

This was an incredible amount of work, and I can't thank you enough for it. Your attention to detail here is absolutely amazing.

Because this PR is rather old now, I was having issues merging. I should have merged long ago, but since then there have been quite a few updates. Instead, I tried to go line by line through all of your suggestions and make all of the appropriate fixes within a broader PR to bring the docs back up to date, remove all broken links, etc. This will be an ongoing project for me over the course of the next few weeks in an effort to make sure everything is working as needed again.

I am going to close this for now as I'm sending in another PR to address these issues, but I wanted to say again thank you so much for all of your effort here. And I sincerely apologize for now getting to this when you initially sent in the PR. I really appreciate all of the hard work you put into this!

I hope all is well!