Feature/#78 refresh intro and preface

[kito99]

Updated preface and rewrote most of the intro. I'd love feedback on the following:

• Prose and depth of the topics; I tried to be more succinct and high level.
• Anything incorrect? The biggest thing I'm wondering about is my characterization of CDI managed beans as Jakarta EE components: https://github.com/jakartaee/jakartaee-tutorial/pull/84/files#diff-884a5f3e8ec08cf536a3c752daf5e9801a5516efca127d8552ee7b5f592bb2fcR12
• New image colors/guidelines

I'd prefer comments directly in the PR; if you want to see what it looks like deployed, I updated the main build to use this branch for Jakarta EE 10, so you can see it here: https://jakartaee.github.io/jakartaee-documentation/jakartaee-tutorial/current/. This way you can easily switch back to the old version by changing to 9.1 in the upper right-hand corner.

[ivargrimstad]

Replace CDI managed bean components with CDI managed beans. Otherwise LGTM

[kito99]

Technically, the preface should be in the index above the intro as it is for 9.1.

[kito99]

The colors of the last two images don't match.

[kito99]

Proofread once more.

[kito99]

Change "Jakarta EE Services" heading to "Jakarta EE Services and Profiles" and mention that which profiles you can access depends on the server, and refer to another section (how do I get it?).

[kito99]

Add table and figure captions, and link to them as we do elsewhere in the tutorial.

[kito99]

Created separate tickets for the tasks above.