[ADD] Manufacturing: Continuous product improvement

[hojo-odoo]

This PR adds a new doc detailing suggestions for implementing the continuous improvement methodology for manufacturing.

[robodoo]

[hojo-odoo]

Hey @jero-odoo,

This doc is ready for the first round of review.

Thanks, John

[hojo-odoo]

Hey @ksc-odoo,

This doc is ready for final review.

Thanks, John

[hojo-odoo]

Hey @samueljlieber,

This doc is ready for technical review.

Thanks, John

[hojo-odoo]

@robodoo r+

[hojo-odoo]

@robodoo r+

[robodoo]

This PR is already reviewed, reviewing it again is useless.

[robodoo]

@samueljlieber retry makes no sense when the PR is not in error.