Add v2/search

[Deleplace]

Integrating the Search legacy bundled service in the appengine/v2 client.

The source is the same as v1:

# Copy the Search source files into v2
cp -R ./appengine/search ./appengine/v2/
cp -R ./appengine/internal/search ./appengine/v2/internal

# Fix import paths
sed -i "" "s/\"google.golang.org\/appengine/\"google.golang.org\/appengine\/v2/" ./appengine/v2/search/search.go
sed -i "" "s/\"google.golang.org\/appengine/\"google.golang.org\/appengine\/v2/" ./appengine/v2/search/search_test.go
sed -i "" "s/\"google.golang.org\/appengine/\"google.golang.org\/appengine\/v2/" ./appengine/v2/internal/search/search.pb.go

[Deleplace]

CC @ludoch

[ludoch]

Great! Can you also change the copyright year and license text in missing files( proto for example)?

[Deleplace]

Done

[jama22]

FWIW, I'd be hesitant to merge this PR in without knowing more about the future of Search API

[ludoch]

Valentin, the plan for adding search has now be approved. we can proceed with this PR.
Thanks for your patience and help there.

[Deleplace]

Awesome, please review and merge

[ludoch]

Valentin, do you know more about the commits that need to be signed? Is it on your side?