[release-1.22] docs: break apart the ambient getting start guide (WIP)

[istio-testing]

Manual cherrypick required.

#15168 failed to apply on top of branch "release-1.22":

Applying: break apart the ambient getting start guide
Applying: wip
Applying: wip
Applying: fix linter issues
Applying: wip
Applying: add tests
Applying: Craig's first edits
Applying: lint fixes
Applying: Fix tests
Applying: fix tests
Applying: test for #15200 workaround
Applying: fix tests (thanks Faseela for helping me get them running locally!)
Applying: Fix the snip generator?
Applying: remove Wasm test because it depends on snips we're moving around
Using index info to reconstruct a base tree...
M	content/en/docs/ambient/usage/extend-waypoint-wasm/index.md
M	go.mod
Falling back to patching base and 3-way merge...
Auto-merging go.mod
CONFLICT (content): Merge conflict in go.mod
Auto-merging content/en/docs/ambient/usage/extend-waypoint-wasm/index.md
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0014 remove Wasm test because it depends on snips we're moving around
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

[zirain]

fxied by #15346