Add CKKS-only mode for functional bootstrapping

[yspolyakov]

Prerequisite steps

1. Add optimization for normal CKKS bootstrapping (decoding before ModRaise)
2. Add optimization for precomputing the coefficients in PS
3. Integrate regular and functional CKKS bootstrapping
4. Add the functionality and examples for uniform ternary secrets for all modes of functional bootstrapping

Design notes

1. For FIXEDMANUAL, add granular support for different scaling factors
2. Initially, add separate precomputations for CKKS bootstrapping and CKKS functional bootstrapping. Later, we can combine them by storing only the maximum level plaintext and then cutting the levels.