doc: delete 'deploying for the first time' in deployment.md
doc: delete 'deploying for the first time' in deployment.md

It seems easy for someone new to x/build services and looking up how to
deploy one for the first time to mistake the "deploying for the first
time" section as being applicable to them. In reality, it shows commands
that are only relevant when creating new services, which we do rarely.

There are many useful but less-frequently used kubectl commands (apply,
create, etc.) that are already documented elsewhere, and we benefit
little from repeating them here. Remove this section to reduce possible
confusion and to make the deployment document shorter.

(If we want to add these back in the future, they should probably go
under a clear "advanced / infrequent use" section or a separate file.)

Change-Id: I930f463e5800f41f1e815c791b6e48153760a9d9
Reviewed-on: https://go-review.googlesource.com/c/build/+/418534
Run-TryBot: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>
Auto-Submit: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@golang.org>
TryBot-Result: Gopher Robot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Michael Knyszek <4473450dc5c88f06e1fb787f303d7805ec2aee65@google.com>
Reviewed-by: Dmitri Shuralyov <d181b7fea0ec87c86ba5a890ab716db52498e3ba@google.com>

golang/build,golang/build,golang/build,golang/build