PR: Support for OBJECT ENCODING

[sashpawar11]

This PR adds support for OBJECT ENCODING and closes #964

This PR consists of additional updates suggested on the previous PR #977 and supersedes it.

Changes :

• Support added for OBJECT ENCODING subcommand, supporting the relevant encoding types available in dicedb.
• Handled types and encoding using switch cases as opposed to the previous implementation in #977
• Integration tests cover all the cases in-depth.
• Unit test cases cover basic test coverage for the subcommand.

Note:

• The tests do not contain a case for the encoding type 'setint' ( ObjEncodingSetInt), as currently we do not encode sets as ints. We can add this case in the future when we integrate the functionality for encoding sets as ints.

Supported Object Types and Object Encoding:

Object Type	Object Encoding
string	raw
string	embstr
int	int
bytelist	deque
bitset	bf
json	json
bytearray	bytearray
set	setstr
set	setint
hashmap	hashmap
sortedset	btree

[sashpawar11]

Hi @lucifercr07 @JyotinderSingh @apoorvyadav1111 - have added the new changes in this PR based on the comments in the old PR. Please review.

Thankyou.