feat: add MLE application template

[DimaNike]

[PR] [Enhancement] MLE application template #255

## Description
mle-app template can be used to generate MLE basic application that can be built and deployed to the database. Database credentials should be provided via existing mechanism by answering questions during the application creation process. In addition, MLE application template requires SQLcl path to be specified.

Fixes #255

## Type of change
- [ ] Bug fix (non-breaking change which fixes an issue)
- [x ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
- [ ] This change requires a documentation update

## How Has This Been Tested?
Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

- [ ] Test A
- [ ] Test B

## Checklist:
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas
- [x] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings/errors
- [n/a] I have added tests that prove my fix is effective or that my feature works
- [n/a] New and existing unit tests pass locally with my changes

[LeonSilva15]

the spacing is inconsistent in templates/mle-ts-sample/src/index.ts and the rest of the js and ts files, this one looks to be spaced with tabs, and others with 2 spaces, I suggest using 4 spaces, otherwise the linter could be annoying

thanks @DimaNike, good job

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