drone: Update .drone.yml for GHA workflows

Update .drone.yml by running `make dronegen` to update the following
pipelines to call GitHub Actions to build instead of building on Drone:

build-linux-amd64
build-linux-amd64-fips
build-linux-386
build-linux-arm64
build-linux-arm

Add two new pipelines for building AMIs and OCIs on GHA:

build-legacy-amis
build-oci

Remove the following pipelines as the build of deb/rpm packages are done
within the above pipelines on GitHub Actions now and the ami/oci
pipelines have been replaced:

build-linux-amd64-deb
build-linux-amd64-fips-deb
build-linux-amd64-centos7-rpm
build-linux-amd64-centos7-fips-rpm
build-linux-386-deb
build-linux-386-rpm
build-linux-arm64-deb
build-linux-arm64-rpm
build-linux-arm-deb
build-linux-arm-rpm
build-oss-amis
build-ent-amis
teleport-container-images-branch-tag

Remove the following pipelines as AMD64 builds are always centos7 builds, but
we were just doing it twice. No need for these any more, as the GHA workflow
will build the release artifacts for these with the centos7 targets:

build-linux-amd64-centos7
build-linux-amd64-centos7-fips

The pipelines were added/removed using the following script, followed by
`make dronegen`:

AWK_SCRIPT='
/^---$/ { printf "%s", accumulator; accumulator = "" }
/^---$/ || accumulator { accumulator = accumulator $0 "\n" }
/^name: / {
	drop = $2 == to_remove
	if ($2 == before && to_add) {
		printf "---\nname: %s\n", to_add
	}
	if (!drop) { printf "%s", accumulator }
	accumulator = ""
	next
}
!drop && !accumulator { print }
ENDFILE { printf "%s", accumulator }'

toremove=(
	build-linux-amd64-{centos7,centos7-fips}
	build-linux-amd64-{deb,fips-deb,centos7-rpm,centos7-fips-rpm}
	build-linux-386-{deb,rpm}
	build-linux-arm64-{deb,rpm}
	build-linux-arm-{deb,rpm}
	build-{oss,ent}-amis
	teleport-container-images-branch-tag
)
add_before=build-buildboxes
toadd=(
	build-legacy-amis
	build-oci
)

for pipeline in "${toremove[@]}"; do
	gawk -i inplace -v to_remove=$pipeline "$AWK_SCRIPT" .drone.yml
done
for pipeline in "${toadd[@]}"; do
	gawk -i inplace -v to_add=$pipeline -v before=$add_before "$AWK_SCRIPT" .drone.yml
done