Improve Documentation for Build-level Source Block

The docs for top-level and build-level source blocks did not make it clear enough, early enough in the page, how packer merges their contents and fails when ambiguities  arise from redefinition. I know the info it there, but it's at the end and I feel that my modification shortens the page overall while putting the most useful info front and center. 

Also, there is simply an error in the note at the end of this page, which further confuses the situation for new readers trying to use HCL and reuse source blocks. It's referring to a non-existent amazon source which is probably a past copy/paste error. 

It took me a day to get re-usable source blocks working, bc I skimmed the page at first (I know slap my wrist), but didn't really grasp what it was saying in the Note at the end, and found it confusing. It wasn't until I found the Issues and PRs related to this feature getting added last April/May that I realized how it was implemented that I started to grasp what this was saying.

fix uint8

Co-authored-by: Sylvia Moss <moss@hashicorp.com>

* Allow locals to be delcared as individual blocks, and give them the Sensitive flag

* add docs for new local block

* linting

* add tests

* modified parsing to use schema, check for dupes properly

* update comment

fix wording a liiitle

* add tests for duplicate variables definition in two different files

* remove unnecessary slice initialisation

* fix crash by returning when decode error is hit

* parseLocalVariables: only treat a local vars if its not nil

also return in case of error
return locals in case of error too

* fix duplicate_locals test for windows
Co-authored-by: Adrien Delorme <azr@users.noreply.github.com>

create util function in hcl2 template that will load config values into hcl values without panicing if it finds something it cannot handle

* Test against deployment url

* Remove infinite redirect configuration

* Add DEPLOYMENT_URL for builds against master

* website: Update README

* tip on seconds

* Test with GHA timeout_minutes clause

* Add continue on error for poll job

* Add empty url check

* Move to pull-request path filter

* Remove www for packer.io

* Apply suggestions from code review

* Update path filter

Vercel deploys on any change under the website directory.

* Use custom action as test
Co-authored-by: Adrien Delorme <azr@users.noreply.github.com>

remove confusing from_scratch reference which is not relevant in this…

Update Ansible local links

enable Packer fmt to read from stdin

yandex/update-dump-method

(1) Add Data Sources docs

* change beta tag

* remove beta tag from hcl2_upgrade comment

* add a partial to describe the legacy json limitations

* exclude legacy category from templates until it is deployed to the website

Co-authored-by: Adrien Delorme <azr@users.noreply.github.com>