Modify repo structure to follow `provider/` convention path

[pose]

Related to: pulumi/pulumi-std#118

[pose]

After moving go.mod and go.sum to the providers folder in pulumi-pulumiservice, I am getting the following error:

> $ make
make: *** No rule to make target `provider/*.go', needed by `bin/pulumi-gen-pulumiservice'.  Stop.

This is caused since the provider doesn't have files on that folder. Here's the relevant Makefile snippet:

bin/$(CODEGEN): provider/*.go provider/go.* .make/upstream
	(cd provider && go build $(PULUMI_PROVIDER_BUILD_PARALLELISM) -o $(WORKING_DIR)/bin/$(CODEGEN) -ldflags "$(LDFLAGS_PROJ_VERSION) $(LDFLAGS_EXTRAS)" $(PROJECT)/$(PROVIDER_PATH)/cmd/$(CODEGEN))

The wildcard expansion happens in the rule for bin/$(CODEGEN), so that each existing ‘.go’ file becomes a prerequisite and will be recompiled if necessary. But that make rule is wrong. Adapted from [the Make manual section "Pitfalls of Using Wildcards":

When a wildcard matches no files, it is left as it is, so then bin/$(CODEGEN) will depend on the oddly-named file *.go. Since no such file is likely to exist, make will give you an error saying it cannot figure out how to make *.go

Which is exactly the error I am getting above.

I believe the original author/s intention was to signal a dependency on go.mod, go.sum, and all the .go files in the providers/ folder. Hence, the target needs to be re-built every time those files are changed. The correct way to achieve that is:

GOSRCS = $(shell find ./provider -type f -name '*.go')
GOMODSUM = $(shell find ./provider -type f -name 'go.*')
bin/$(CODEGEN): $(GOSRCS) $(GOMODSUM) .make/upstream
	(cd provider && go build $(PULUMI_PROVIDER_BUILD_PARALLELISM) -o $(WORKING_DIR)/bin/$(CODEGEN) -ldflags "$(LDFLAGS_PROJ_VERSION) $(LDFLAGS_EXTRAS)" $(PROJECT)/$(PROVIDER_PATH)/cmd/$(CODEGEN))

[blampe]

After moving go.mod and go.sum to the providers folder in pulumi-pulumiservice

If the module is already at the repo root we should try to keep it there (#1238 explains why). There's a ci-mgmt config that lets us override the module location.

[pose]

1. .PHONY target that calls go build

OR

1. empty go file + change glob to use {{ .Config.ModulePath }}/go.*

OR

1. GOSRC/GOMODSUM

[pose]

Went with the "empty go file + change glob to use {{ .Config.ModulePath }}/go.*" approach. Resolving in favor of #2047