Bonds of any authority or of any agency or instrumentality designated or appointed by an authority are declared to be issued for an essential public and governmental purpose and to be public instrumentalities and, together with interest and income thereon, shall be exempt from taxes and from the Connecticut Uniform Securities Act. The property of an authority or of any agency or instrumentality designated or appointed by an authority shall be exempt from all local and municipal taxes, except that when any commercial facility is included in a housing project, such facility shall be subject to assessment and taxation in the same manner as other taxable property in the municipality. A municipality may (a) fix a sum, and such sum shall be paid to it annually by the authority, in respect of each project; or (b) agree that the authority shall not pay or be liable to pay any sum whatsoever in respect of a project or projects for any year or years; or (c) agree with an authority or the federal government upon the sum to be paid by the authority for any year or years in respect of a project or projects, or accept or agree to accept a fixed sum or other consideration in lieu of such payment.