Fix build from submodules (broker, transaction coordinator)

[nicoloboschi]

Motivation

Currently running mvn install -DskipTests from pulsar/pulsar-broker and pulsar/pulsar-transaction/coordinator is failing due to (see also #11030)

[ERROR] Failed to generate lightproto code for [/home/hangc/Downloads/tmp/pulsar/pulsar-broker/src/main/proto/TransactionPendingAck.proto, /home/hangc/Downloads/tmp/pulsar/pulsar-broker/src/main/proto/ResourceUsage.proto]: java.lang.IllegalStateException: Imported proto pulsar-common/src/main/proto/PulsarApi.proto not found. (null)
java.lang.RuntimeException: java.lang.IllegalStateException: Imported proto pulsar-common/src/main/proto/PulsarApi.proto not found. (null)
    at io.protostuff.parser.Proto.importProto (Proto.java:316)
    at io.protostuff.parser.ProtoParser.header_import (ProtoParser.java:1431)
    at io.protostuff.parser.ProtoParser.statement (ProtoParser.java:336)
    at io.protostuff.parser.ProtoParser.parse (ProtoParser.java:165)
    at io.protostuff.parser.ProtoUtil.loadFrom (ProtoUtil.java:52)
    at io.protostuff.parser.ProtoUtil.loadFrom (ProtoUtil.java:60)
    at io.protostuff.parser.ProtoUtil.loadFrom (ProtoUtil.java:90)
    at com.github.splunk.lightproto.generator.LightProtoGenerator.generate (LightProtoGenerator.java:42)
    at com.github.splunk.lightproto.maven.plugin.LightProtoMojo.generate (LightProtoMojo.java:62)
    at com.github.splunk.lightproto.maven.plugin.LightProtoMojo.execute (LightProtoMojo.java:94)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo (DefaultBuildPluginManager.java:137)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:210)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:156)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute (MojoExecutor.java:148)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:117)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject (LifecycleModuleBuilder.java:81)
    at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build (SingleThreadedBuilder.java:56)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute (LifecycleStarter.java:128)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:305)
    at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:192)
    at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:105)

Modifications

Added maven-properties-plugin on initalize Maven phase, which sets two system properties used by protostuff (used by protolight plugin) 

• proto_path: added the root directory in order to resolve imports like pulsar-common/src/main/proto/PulsarApi.proto
• proto_search_strategy: value 2 (default value is not working, I feel it's buggy)

see https://github.com/protostuff/protostuff/blob/master/protostuff-parser/src/main/java/io/protostuff/parser/DefaultProtoLoader.java for more context

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): yes, but a compile time (added maven-properties-plugin)
• The public API: no
• The schema: no
• The default values of configurations: no
• The wire protocol: no
• The rest endpoints: no
• The admin cli options: no
• Anything that affects deployment: no

Documentation

For this PR, do we need to update docs?

Not needed

[eolivelli]

Looks good to me.
Please revert formatting

[eolivelli]

LGTM

@hangc0276 @lhotari PTAL

[hangc0276]

Good job!

[lhotari]

LGTM

[eolivelli]

merged to master branch, nice work @nicoloboschi