[Link] Relevance of title attributes

## Feature Request

In French-speaking countries, for accessibility audit we use the RGAA accessibility guidelines, for the links it's a little stricter than WCAG.

**Is your feature request related to a problem? Please describe.**
For each text link with a link title (title attribute), the content of this attribute is not enought relevant for RGAA auditors.

**Describe the solution you'd like**
The link title must contain at least the textual content.

To take into account to go further :
- If a title proposal is entered manually by the editor, and if this proposal is different from the textual content then we will use a concatenation of these two elements for the title attribute
- If a proposed title is entered manually by the writer, and if the textual content is included in the manually entered title proposal then the title attribute will consist only of the proposed title
- If a title proposal is entered manually by the editor, and if the textual content is stricly equal to this proposal then the title attribute shouldn't be generated (shouldn't display anything on hover)

In the code, edit "PN_LINK_TITLE_ATTRIBUTE" around line 130 of aem-core-wcm-components/bundles/core/src/main/java/com/adobe/cq/wcm/core/components/internal/link/LinkBuilderImpl.java

**Example**
`My label`

- link title = "My label - new window"
- textual content = "My label"

**Documentation**

- RGAA 6.1.5 : https://accessibilite.numerique.gouv.fr/methode/criteres-et-tests/#6.1.5 (In french)
- WCAG 2.4.4 : https://www.w3.org/WAI/WCAG21/Understanding/link-purpose-in-context.html
- WCAG H33 : https://www.w3.org/TR/WCAG-TECHS/H33.html
- RAWeb 6.1.5 : https://accessibilite.public.lu/fr/raweb1/criteres.html#test-6-1-5 (In french)

Start in aem-core-wcm-components/bundles/core/src/main/java/com/adobe/cq/wcm/core/components/internal/link/LinkBuilderImpl.java, around PN_LINK_TITLE_ATTRIBUTE. Trace how the link title and textual content are obtained, then compare the behavior with the RGAA 6.1.5 rules and examples in the issue. Done means the generated title follows each stated equality, inclusion, and concatenation case.

Written by the indexing model from the issue text.