Add floating keyboard resizing option

[naveensingh]

Checklist

• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the request will be dismissed otherwise.
• This issue contains only one feature request.
• I have read and understood the contribution guidelines.

Feature description

Ability to resize keyboard directly using a resize handle instead of using hardcoded percentages (doesn't work well).

Examples:

Why do you want this feature?

• Better UI/UX.
• Other keyboards have similar options.

Additional information

Related:

• ability to manually input keyboard height #125
• i need to set a different keyboard height for both screen orientations each #84

Notes:

• Height in portrait mode shouldn't affect landscape mode and vice versa.
• Ideally the keyboard should have a preference menu with options like resize, settings etc. but a new button on the top bar will also work for now.