OAL tool module established

[wu-sheng]

1. [PR [OAL refactor step 1]Refactor dispatcher manager #2006] Make hard codes in DispatcherManager goes away.
2. [In this PR] Move genereated package to an maven module(a.k.a. a jar in oal-libs), named generated-analysis
3. [In this PR] Move the oal-tool back into the main repo, and could generate codes during mvn compile.

[wu-sheng]

The oap-server/generate-tool module includes the source codes of compiling tool. This tool is already integrated
maven compile phase. So, unless you want to change the tool source codes, you don't need to set anything.

Run ./mvnw compile or ./mvnw package, the generated codes of the oal script are in oap-server/generate-tool/target/generated-sources/oal/*.

[wu-sheng]

@liuhaoyang The repository structure has changed. OAL-tool has been integrated.

[JaredTan95]

LGTM，This is a very meaningful refactoring. And I compiled in my local env, It feels good to use.

[JaredTan95]

How about adding the same we only recommend you to do this when you plan to build your own UI based on the customization analysis core. thing here? :-D

[wu-sheng]

I remember I used to put these words somewhere else? If you think we should put same in here. Feel free to add.

[wu-sheng]

@JaredTan95 I am merging, if you want to add this, send another PR:)

[liuhaoyang]

LGTM

[coveralls]

Coverage increased (+2.3%) to 14.314% when pulling 870c2dc on oal-tool-movein into c141376 on master.