Add Bootstrap 5 floating labels

[coder2000]

Add an option to use floating labels from bootstrap 5, still requires the user to add a placeholder to their fields.

[coveralls]

Pull Request Test Coverage Report for Build 163

• 17 of 19 (89.47%) changed or added relevant lines in 2 files are covered.
• 13 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-1.5%) to 98.402%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/comfy_bootstrap_form/form_builder.rb	14	16	87.5%
<!--	Total:	17	19

Files with Coverage Reduction	New Missed Lines	%
test/comfy_bootstrap_form/custom_fields_test.rb	6	87.23%
lib/comfy_bootstrap_form/form_builder.rb	7	94.35%
<!--	Total:	13

Totals
Change from base Build 154:	-1.5%
Covered Lines:	985
Relevant Lines:	1001

---

💛 - Coveralls