[Rachana] Add contextual chaining rule and glyph decomposition to suppress dotted circle before ാം and ാമത്തെ

Add a 'ccmp' Glyph Decomposition lookup to map dotted circle to NULL (empty glyph)
Add a 'calt' Contextual Chaining Substitution lookup to apply 'ccmp' on pattern "(digit|hyphen)ാ(ം|മ)"
Test case: 1-ാം, 1-ാമത്തെ, 1ാം, 1ാമത്തെ

Signed-off-by: Rajeesh K Nambiar <rajeeshknambiar@gmail.com>